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College of Agricultural & Life Sciences

Physical Address:
E. J. Iddings Agricultural Science Laboratory
606 S Rayburn St

Mailing Address:
875 Perimeter Drive MS 2331
Moscow, ID 83844-2331

Phone: 208-885-6681

Fax: 208-885-6654

Email: ag@uidaho.edu

Web: uidaho.edu/cals/potatoes

Location

Mailing Address:
1693 S 2700 W
Aberdeen, ID 83210

Phone: 208-397-4181

Fax: 208-397-4311

Web: uidaho.edu/cals/aberdeen

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Mailing Address:
3793 North 3600 East
Kimberly ID 83341-5076

Phone: 208-423-4691

Fax: 208-423-6699

Web: uidaho.edu/cals/kimberly

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Mailing Address:
29603 U of I Lane
Parma, ID 83660-6699

Phone: 208-722-6701

Fax: 208-722-6708

Web: uidaho.edu/cals/parma

Location

News, updates & conferences

Pest Alerts

Sept. 10, 2020

Final psyllid trap capture report for the 2020 season

This week we had traps deployed in 45 of the 65 fields (69%) monitored this year; 20 fields had been vine killed and were not monitored. We found a total of 105 psyllids across 16 (35%) of the 45 fields.

Psyllids were collected on sticky traps in potato in the following counties: Canyon (five fields), Owyhee (one field), Elmore (four4 fields), Twin Falls (five fields) and Power (one field).

From last week’s samples, no psyllids tested positive for Lso (liberibacter), the bacterium associated with zebra chip disease (ZC).

We are not including “heat maps” this week given that they tend to show skewed patterns with smaller sample sizes.

This week concludes our 2020 psyllid monitoring program, following recommendations from our ZC Advisory Committee of shortening the duration. However, we will report on the last set of Lso results next week.

Total psyllid captures are still down from two weeks ago and based on previous years’ observations we would expect their numbers to continue to reduce; however, psyllids likely will continue dispersing among the remaining fields as vine kill continues. Overall captures of psyllids this season were higher than the last two seasons, though still nowhere near as high as the “epic” years of 2016 and 2012. Thus far, we have also seen our lowest incidence of Lso-positive psyllids yet (0.4%). Together, we expect that the modest psyllid abundance and very low Lso incidence this year should result in relatively low incidence of ZC in harvested tubers. But remember that, at least in our experiments with Russet Burbank, some risk of ZC remains if infection occurs within one-two  weeks before vine kill.

Updated weekly report

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Sept. 10, 2020

Final psyllid trap capture report for the 2020 season

This week we had traps deployed in 45 of the 65 fields (69%) monitored this year; 20 fields had been vine killed and were not monitored. We found a total of 105 psyllids across 16 (35%) of the 45 fields.

Psyllids were collected on sticky traps in potato in the following counties: Canyon (five fields), Owyhee (one field), Elmore (four4 fields), Twin Falls (five fields) and Power (one field).

From last week’s samples, no psyllids tested positive for Lso (liberibacter), the bacterium associated with zebra chip disease (ZC).

We are not including “heat maps” this week given that they tend to show skewed patterns with smaller sample sizes.

This week concludes our 2020 psyllid monitoring program, following recommendations from our ZC Advisory Committee of shortening the duration. However, we will report on the last set of Lso results next week.

Total psyllid captures are still down from two weeks ago and based on previous years’ observations we would expect their numbers to continue to reduce; however, psyllids likely will continue dispersing among the remaining fields as vine kill continues. Overall captures of psyllids this season were higher than the last two seasons, though still nowhere near as high as the “epic” years of 2016 and 2012. Thus far, we have also seen our lowest incidence of Lso-positive psyllids yet (0.4%). Together, we expect that the modest psyllid abundance and very low Lso incidence this year should result in relatively low incidence of ZC in harvested tubers. But remember that, at least in our experiments with Russet Burbank, some risk of ZC remains if infection occurs within one-two  weeks before vine kill.


Sept. 3, 2020

This week we had traps deployed in 48 of the 65 fields (73%) monitored this year; 17 fields have been vine killed and will no longer be monitored. We found a total of 92 psyllids across 18 (37%) of the 48 fields.

Psyllids were collected on sticky traps in potato in the following counties: Canyon (seven fields), Owyhee (one field), Elmore (four fields), Twin Falls (four fields) and Power (two fields).

From last week’s samples, no psyllids tested positive for Lso (liberibacter), the bacterium associated with zebra chip disease (ZC). However, due to shipping delays from last week, a few Lso results will be delayed until next week.

We are not including “heat maps” this week given that they tend to show skewed patterns with smaller sample sizes.

Total psyllid captures were down considerably this week, which was related to fewer fields being monitored but also fewer captures in most of the remaining fields. It appears that we saw peak seasonal captures last week. However, remember that, at least in our experiments with Russet Burbank, some risk of ZC remains if infection occurs within one-two weeks before vine kill.


Aug. 28, 2020

This week we had traps deployed in 60 of the 65 fields (92%) monitored this year; five fields have been vine killed and will no longer be monitored. We found a total of 199 psyllids across 35 (58%) of the 60 fields.

Psyllids were collected on sticky traps in potato in the following counties: Payette (one field), Canyon (12 fields), Owyhee (two fields), Gem (one field), Elmore (5 fields), Gooding (one field), Jerome (four fields), Twin Falls (six fields) and Power (three field).

From last week’s samples, one psyllid (collected in Canyon County) tested positive for Lso (liberibacter), the bacterium associated with zebra chip disease (ZC). However, due to shipping delays from last week, a few Lso results will be delayed until next week.

“Heat maps” of this week’s results are included on the U of I and WSU websites (https://potatoes.decisionaid.systems/idaho). “Heat maps” describe predicted psyllid densities across the landscape, based on our trap counts and on predictive models developed over six years of psyllid monitoring in Idaho. The heat maps graphically reflect the relatively high abundance of psyllids collected in some fields in Canyon and Twin Falls counties.

Total psyllid captures were the highest we have observed this year, which is not surprising given that captures typically increase toward the end of the season, likely in part due to increase dispersal in relation to senescence and vine kill. We continue to urge growers to maintain their IPM programs. Tubers may still be at high risk of ZC if infection occurs three or more weeks before vine kill; in our experiments with Russet Burbank, risk diminishes within one-two weeks before vine kill but does not disappear.


Aug. 20, 2020

This week we had traps deployed in 62 of the 65 fields (95%) monitored this year; three fields have been vine killed and will no longer be monitored. We found a total of 124 psyllids across 26 (41%) of the 62 fields. Of the 124 psyllids captured, 59 (47%) were found across three fields at University of Idaho Kimberly Research and Extension Center (KREC).

Psyllids were collected on sticky traps in potato in the following counties: Payette (one field), Canyon (10 fields), Owyhee (one field), Gem (two fields), Elmore (five fields), Jerome (two fields), Twin Falls (four fields) and Power (one field).

From last week’s samples, no psyllids so far have tested positive for Lso (liberibacter), the bacterium associated with zebra chip disease (ZC). However, due to shipping delays from last week, a few Lso results will be delayed until next week.

“Heat maps” of this week’s results are included on the U of I and WSU websites (https://potatoes.decisionaid.systems/idaho). “Heat maps” describe predicted psyllid densities across the landscape, based on our trap counts and on predictive models developed over six years of psyllid monitoring in Idaho. The heat maps graphically reflect the relatively high abundance of psyllids collected in some fields in Twin Falls County.

Total psyllid captures dropped notably relative to last week, though high captures were still observed at KREC. We continue to urge growers to have their IPM programs in place, especially where psyllid numbers have been relatively high. Tubers may still be at high risk of ZC if infection occurs three or more weeks before vine kill; in our experiments with Russet Burbank, risk diminishes within one-two weeks before vine kill but does not disappear.


Aug. 13, 2020

This week we had traps deployed in 64 of the 65 fields (98%) monitored this year; one field has been vine killed and will no longer be monitored. We found a total of 181 psyllids across 25 (39%) of the 64 fields. Of the 181 psyllids captured, 115 psyllids (63%) were found across three fields at University of Idaho Kimberly Research and Extension Center (KREC). Because this is an unusually high number of psyllids, we will only be testing a subset for Lso at this time.

Psyllids were collected on sticky traps in potato in the following counties: Payette (one field), Canyon (eight fields), Owyhee (one field), Gem (one field), Elmore (two fields), Gooding (one field), Jerome (one field), Twin Falls (eight fields) and Power (two fields).

From last week’s samples, no psyllids tested positive for Lso (liberibacter), the bacterium associated with zebra chip disease (ZC).

“Heat maps” of this week’s results are included on the U of I and WSU websites (https://potatoes.decisionaid.systems/idaho). “Heat maps” describe predicted psyllid densities across the landscape, based on our trap counts and on predictive models developed over six years of psyllid monitoring in Idaho. The heat maps graphically reflect the relatively high abundance of psyllids collected in some fields in Twin Falls County.

Total psyllid captures were higher this week; however, captures for most fields were lower, and this increase can be attributed to surprisingly high captures at KREC. Captures were relatively high in a few other Magic Valley fields, though not to the extent observed at KREC. The reason for this is not clear. We continue to urge growers to have their IPM programs in place.


Aug. 6, 2020

This week we had traps deployed in 64 of the 65 fields (98%) monitored this year; one field has been vine killed and will no longer be monitored. We found a total of 132 psyllids across 31 (48%) of the 64 fields, though we are still waiting for traps from one site in Canyon county.

Psyllids were collected on sticky traps in potato in the following counties: Payette (one field), Canyon (nine fields), Owyhee (two field), Gem (two fields), Elmore (4 fields), Jerome (one field), Twin Falls (10 fields), and Oneida (one field).

From last week’s samples, no psyllids tested positive for Lso (liberibacter), the bacterium associated with zebra chip disease (ZC). We are waiting on results for two psyllids (one each from Gem and Minidoka counties), which we should have next week.

“Heat maps” of this week’s results are included on the U of I and WSU websites (https://potatoes.decisionaid.systems/idaho). “Heat maps” describe predicted psyllid densities across the landscape, based on our trap counts and on predictive models developed over six years of psyllid monitoring in Idaho. The heat maps graphically reflect the relatively high abundance of psyllids collected in some fields in the Treasure Valley and around Twin Falls.

Psyllid captures were slightly higher this week, though similar to total captures during early August last year. We continue to urge growers to have their IPM programs in place.


July 30, 2020

Another Lso-positive psyllid

This week we had traps deployed in 65 of the 65 fields (100%) monitored this year; we found a total of 114 psyllids across 28 (43%) of the 65 fields.

Psyllids were collected on sticky traps in potato in the following counties: Payette (one field), Canyon (10 fields), Owyhee (one field), Gem (two fields), Elmore (two fields), Gooding (one field), Jerome (two fields), Twin Falls (seven fields), Minidoka (one fields) and Power (one field).

From last week’s samples, one psyllid (collected in Twin Falls County) tested positive for Lso (liberibacter), the bacterium associated with zebra chip disease (ZC). This is the second observation of an Lso-positive psyllid in our monitoring program in as many weeks. Overall incidence of Lso still remains relatively low (about 1% through last week).

“Heat maps” of this week’s results are included on the U of I and WSU (https://potatoes.decisionaid.systems/idaho) websites. “Heat maps” describe predicted psyllid densities across the landscape, based on our trap counts and on predictive models developed over six years of psyllid monitoring in Idaho. The heat maps graphically reflect the relatively high abundance of psyllids collected in the Western Treasure Valley.

Psyllid captures were higher this week, though similar to total captures during late July to early August last year. Given this increase and the additional observation of an Lso-positive psyllid, we continue to urge growers to have their IPM programs in place.


July 23, 2020

First Lso-positive psyllids in 2020 Idaho monitoring

This week we had traps deployed in 59 of the 65 fields (91%) monitored this year (though we have not yet received traps from 6 of these fields); we found a total of 83 psyllids across 28 (53%) of the 53 fields with data.

Psyllids were collected on sticky traps in potato in the following counties: Canyon (12 fields), Owyhee (two fields), Gem (two fields), Elmore (three fields), Jerome (one field), Twin Falls (seven fields), Minidoka (two fields) and Oneida (one field).

From last week’s samples, two psyllids tested positive for Lso (liberibacter), the bacterium associated with zebra chip disease (ZC). These hot psyllids were collected from two different fields: one in Twin Falls and one in Jerome County. This is the first observation of Lso-positive psyllids in our monitoring program this year. This is about one week and two weeks later than the first observation of Lso-positive psyllids during 2019 and 2018, respectively.

“Heat maps” of this week’s results are included on the U of I and WSU websites (see links below). “Heat maps” describe predicted psyllid densities across the landscape, based on our trap counts and on predictive models developed over six years of psyllid monitoring in Idaho. These maps, developed in collaboration with WSU, should be used as a guideline, but not a definitive count of the number of insects in any given field at any given point in time. “Low,” “Moderate,” “High” and “Very High” designations are arbitrary categories that illustrate relative abundance and should not be used as “thresholds.” More details on the “heat maps” can be found in Potato Progress Volume XVII, Number 2, Feb. 15, 2017.

Psyllid captures were a bit higher this week, though similar to total captures during late July to early August last year. Given this increase and the first observation this year of Lso-positive psyllids in Idaho, we urge growers to have their IPM programs in place.


Psyllid Update July 16, 2020

This week we had traps deployed in 56 of the 65 fields (86%) monitored this year and we found a total of 42 psyllids across 22 (39%) of the 56 fields.

Psyllids were collected on sticky traps in potato in the following counties: Payette (one field), Canyon (four fields), Gem (two fields), Elmore (one field), Jerome (two fields), Twin Falls (nine fields), Cassia (one field), Power (one field) and Oneida (one field).

The remaining nine fields (across Bingham and Power counties) had traps deployed in them this week, and we will report data from them next week.

Lso testing of last week’s psyllids has been delayed. We plan to report Lso results next week.

There was also an issue with the generation of “heat maps” that we expect to have resolved by next week.

Psyllid captures were similar to last week and similar to this time last year, though we urge growers to watch psyllid numbers closely during the coming weeks.


July 9, 2020

This week we had traps deployed in 56 of the 65 fields (86%) monitored this year and we found a total of 44 psyllids across 22 (39%) of the 56 fields.

Psyllids were collected on sticky traps in potato in the following counties: Payette (one field), Canyon (six fields), Gem (two fields), Elmore (three fields), Jerome (one field), Twin Falls (eight fields) and Minidoka (1 field).

From the last two week’s samples, so far zero psyllids have tested positive for Lso (liberibacter), the bacterium associated with zebra chip disease (ZC). However, we still have one psyllid from last week (collected from Twin Falls county) with pending Lso results.

We apologize for not having “heat maps” yet this week. We expect to have them generated before next week’s update and posted on our website.

Thus far, psyllid captures are similar to this time last year, though we urge growers to watch psyllid numbers closely during the coming weeks.


July 2, 2020

The University of Idaho and our crop consultant collaborators across the state are continuing the monitoring program for potato psyllids, zebra chip disease (ZC) and liberibacter (Lso), the bacterium associated with ZC. The monitoring program covers commercial potato fields throughout southern Idaho and is funded in part by the Idaho Potato Commission and generous in-kind contributions by our collaborators.

Following guidance from our ZC Advisory Committee, we are running a shortened monitoring season beginning at the end of June and continuing for 10 to 12 weeks, using four sticky traps per field at all sites. Complications related to COVID-19 have limited the number of sites being monitored by some of our cooperators, but we expect to still have a total of about 65 fields across the state.

The first set of traps in commercial fields was deployed last week, with quite a few more having been deployed this week. We began monitoring at the Kimberly R&E Center (KREC) during mid-June. During the week of June 22, we captured a total of four potato psyllids among our three monitored fields at KREC.

During the week of June 29, we captured 11 psyllids across the same fields as well as seven psyllids across three commercial fields in Canyon county. Psyllid abundance appears to be fairly low as is typical of June, but we will obtain trap data from many more sites next week.


Sept. 5, 2019 — Psyllid update

This week we had traps deployed in 62 of the 79 fields (78.4 percent) monitored this year, and we found a total of 32 psyllids across 13 (16.4 percent) of the 79 monitored fields. Many of the 79 total fields that we were sampling have been vine-killed.

Psyllids were collected on sticky traps in potato in the following counties: Payette (1 field), Canyon (6 fields), Owyhee (2 fields), Twin Falls (2 fields), Jerome (1 field) and Power (1 field).

All psyllids collected last week tested negative for Lso (liberibacter), the bacterium that causes zebra chip.

Our research with Russet Burbank in Idaho has shown that plants should be protected from infection with the ZC bacterium at least until one week before vine kill to reduce ZC symptoms. Therefore, we continue to urge growers to maintain their IPM programs.

We are not including “heat maps” this week given that they tend to show skewed patterns with smaller sample sizes.

Following recommendations from our ZC Advisory Committee last year, we shortened the duration of our monitoring program. This week we conclude the official monitoring program, though we will continue monitoring fields at the Kimberly Research and Extension Center as well as grower- and crop consultant-submitted samples. We will post any important updates that develop.


Aug. 29, 2019 Psyllid abundance remains relatively steady

This week we had traps deployed in 76 of the 79 fields (96.2 percent) monitored this year, and we found a total of 58 psyllids across 26 (32.9 percent) of the 79 monitored fields. Three of the 79 total fields that we were sampling have been vine-killed.

Psyllids were collected on sticky traps in potato in the following counties: Payette (3 fields), Canyon (10 fields), Elmore (4 fields), Twin Falls (4 fields), Jerome (2 fields) and Cassia (3 fields).

All psyllids collected last week tested negative for Lso (liberibacter), the bacterium that causes zebra chip.

Overall psyllid captures have remained relatively steady over the last few weeks. However, we continue to urge growers to maintain their IPM programs.

“Heat maps” of this week’s results can be found on the U of I and WSU websites linked below. The moderately “hot spot” observed during recent weeks in the western Treasure Valley remains, with another small area of moderate pressure south of Mountain Home.

heat maps of potato psyllid - Aug. 29 east

heat maps of potato psyllid - Aug. 29 west

This was the last sample week for quite a few of our fields, so we likely will not include heat maps next week given that they tend to be skewed with smaller sample sizes.


Aug. 22, 2019

This week we had traps deployed in 78 of the 79 fields (98.7 percent) monitored this year, and we found a total of 52 psyllids across 26 (32.9 percent) of the 79 monitored fields. One of the 79 total fields that we were sampling has been vine-killed.

Psyllids were collected on sticky traps in potato in the following counties: Payette (three fields), Canyon (nine fields), Owyhee (two fields), Elmore (one field), Twin Falls (six fields), Jerome (three fields), Cassia (one field) and Minidoka (one field). 

All psyllids collected last week tested negative for Lso (liberibacter), the bacterium that causes zebra chip.

Overall psyllid captures have remained relatively steady over the last few weeks. However, we continue to urge growers to maintain their IPM programs.

“Heat maps” of this week’s results can be found on the U of I and WSU websites linked below. The “hot spots” observed during recent weeks in the western Treasure Valley have diminished somewhat.

heat maps of potato psyllid - Aug. 22 east heat maps of potato psyllid - Aug. 22 west


Aug. 15, 2019

This week we had traps deployed in 76 of the 79 fields (96.2 percent) monitored this year, and we found a total of 55 psyllids across 24 (30.4 percent) of the 79 monitored fields. One of the 79 total fields that we were sampling has been vine-killed.

Psyllids were collected on sticky traps in potato in the following counties: Payette (two fields), Canyon (11 fields), Owyhee (one field), Elmore (one field), Gooding (one field), Twin Falls (five fields), Jerome (one field), Cassia (one field) and Minidoka (one field).

All psyllids collected last week tested negative for Lso (liberibacter), the bacterium that causes zebra chip.

Overall psyllid captures have remained relatively steady over the last few weeks. However, we continue to urge growers to maintain their IPM programs.

“Heat maps” of this week’s results can be found on the U of I and WSU websites linked below. We continue to observe a “hot spot” in the western Treasure Valley.

heat maps of potato psyllid - Aug. 15 west

heat maps of potato psyllid - Aug. 15 east


Aug. 8, 2019

First psyllid in eastern Idaho this year

This week we had traps deployed in 78 of the 79 fields (98.7%) monitored this year, and we found a total of 73 psyllids across 27 (34.2%) of the 79 monitored fields. However, we are still waiting to receive traps from 3 sites in the Magic Valley. One of the 79 total fields that we were sampling has been vine-killed.

Psyllids were collected on sticky traps in potato in the following counties: Payette (3 fields), Canyon (9 fields), Elmore (2 fields), Gooding (1 field), Twin Falls (6 fields), Jerome (1 field), Cassia (2 fields), Minidoka (2 fields), and Bingham (1 field). This was our first capture of a potato psyllid this year in eastern Idaho, which consistently has shown later first incidence of psyllids and lower abundance overall.

All psyllids collected last week tested negative for Lso (liberibacter), the bacterium that causes zebra chip.

Psyllid captures have fluctuated only a bit over the past three weeks, and thankfully we have not observed hot psyllids since mid-July.

“Heat maps” of this week’s results can be found on the UI and WSU websites linked below. “Hot spots” continue to be observed in the western Treasure Valley.

Levels are moderate near Twin Falls, Caldwell, Nampa and the Jordon Valley. All other areas are low except Grand View and Glenns Ferry.

Low levels detected near Rockford, Moreland, Pingree, Rupert, Iversons and Oakley Basin. No others detected as far as Blackfoot. 

August 1, 2019

Psyllid captures declined a bit this week

This week we had traps deployed in 81 of the 82 fields (98.7%) monitored this year, and we found a total of 67 psyllids across 27 (32.9%) of the 82 monitored fields. However, we are still waiting to receive traps from 19 sites in eastern Idaho. One of the 82 total fields that we were sampling has been vine-killed.

Psyllids were collected on sticky traps in potato in the following counties: Payette (3 fields), Canyon (12 fields), Owyhee (1 field), Elmore (3 fields), Twin Falls (6 fields), Cassia (1 field), and Minidoka (1 field).

All psyllids collected last week tested negative for Lso (liberibacter), the bacterium that causes zebra chip.

Psyllid captures dropped a bit relative to last week; however, we continue to urge growers to maintain their IPM programs, especially given that we have historically seen an increase in captures during August.

Levels are moderate near Caldwell, Glenns Ferry and Twin Falls/Kimberly, with points in between low to undetected.

Low levels detected near Minidoka and Oakley Basin. No others detected as far as Blackfoot.


July 25, 2019

One more Lso-positive psyllid found in Idaho

This week we had traps deployed in 83 of the 83 fields (100%) monitored this year and we found a total of 107 psyllids across 32 (35.9%) of the 83 monitored fields.

Psyllids were collected on sticky traps in potato in the following counties: Payette (3 fields), Canyon (11 fields), Owyhee (2 fields), Elmore (4 fields), Twin Falls (9 fields), Jerome (2 fields), and Cassia (1 field).

From last week’s samples, 1 psyllid tested positive for Lso (liberibacter), the bacterium associated with zebra chip disease (ZC). This hot psyllid was collected from one field in Twin Falls County.

Given the recent incidence of Lso observed in psyllids, we strongly urge growers and crop consultants to maintain their IPM programs.

The uptick in psyllid abundance this week is not surprising given that we historically have seen an increase in captures during late July through August. Abundance of psyllids so far has been higher this year than during the last two, but still not as high as during 2016 when hundreds of psyllids were captured each week during this time.

“Heat maps” of this week’s results are included on the UI and WSU websites (see links below). “Heat maps” describe predicted psyllid densities across the landscape, based on our trap counts and on predictive models developed over six years of psyllid monitoring in Idaho. These maps, developed in collaboration with WSU, should be used as a guideline, but not a definitive count of the number of insects in any given field at any given point in time. “Low,” “Moderate,” “High,” and “Very High” designations are arbitrary categories that illustrate relative abundance and should not be used as “thresholds.” More details on the “heat maps” can be found in Potato Progress Volume XVII, Number 2, 15 February 2017.

Map depicting the area from outside Caldwell to outside of Twin Falls. There are areas of "high" detection outside of Buhl and Caldwell, with most other areas in the low or moderate range.

Map depicting none detected from west of Craters of the Moon to east of Blackfoot and south to near Malad City.


July 18, 2019

First Lso-positive psyllids found in Idaho

This week we had traps deployed in 83 of the 83 fields (100 percent) monitored this year and we found a total of 59 psyllids across 29 (34.9 percent) of the 83 monitored fields.

Psyllids were collected on sticky traps in potato in the following counties: Payette (1 field), Canyon (11 fields), Elmore (3 fields), Twin Falls (10 fields), Jerome (3 fields) and Cassia (1 field).

From last week’s samples, five psyllids tested positive for Lso (liberibacter), the bacterium associated with zebra chip disease (ZC). These hot psyllids were collected from one field in Payette County and two fields in Twin Falls County. In addition, one psyllid collected from a field in Canyon County in mid-June (before our monitoring program had officially started) tested positive for Lso.

Given the incidence of Lso observed in psyllids, we strongly urge growers and crop consultants to maintain their IPM programs.

We apologize for not having “heat maps” yet this week. We hope to have them generated before next week and posted on our website.


July 11, 2019

The 2019 University of Idaho monitoring program for potato psyllids and liberibacter (Lso), the bacterium associated with zebra chip disease (ZC), is underway. Following recommendations from our ZC Advisory Committee last year, we shortened the duration of the program. We also plan to post weekly updates by Thursday each week instead of Friday.

This week, we collected 38 psyllids from sticky cards (across 20 sites).

Psyllids were collected on sticky traps in potato in the following counties: Payette (2 fields), Canyon (7 fields), Owyhee (2 fields), Elmore (3 fields), Twin Falls (3 fields), Jerome (2 fields) and Minidoka (1 field).

We had traps deployed in 53 of the 83 fields (63.8 percent) monitored this year and found psyllids in 19 of the monitored fields (37.7%).

During the previous week (before the monitoring program officially began), we collected 14 psyllids across 7 of 25 fields that were monitored (psyllids were captured in Payette, Canyon and Owyhee counties).

All psyllids tested so far have been negative for Lso. Nevertheless, we urge growers and crop consultants to maintain their IPM programs.

“Heat maps” of this week’s results will not be made given that a relatively low number of psyllids and sites (traps in several fields were just deployed this week) tends to result in skewed maps.


June 28, 2019

The University of Idaho, in collaboration with crop consultants across the state, will continue our monitoring program for potato psyllids, zebra chip disease and liberibacter (Lso), the bacterium associated with zebra chip. The monitoring program covers commercial potato fields throughout southern Idaho and is funded in part by the Idaho Potato Commission, USDA and generous in-kind contributions by our collaborators.

Following recommendations from our ZC Advisory Committee last year, we are shortening the duration of the program. We still plan to monitor about 100 fields across the state, but only with four sticky traps per field rather than the more intense sampling that was conducted on some fields in the past.

The first official deployment of sticky traps for the program will occur next week. However, following earlier than usual observation of potato psyllids in Oregon, we began deploying traps on a limited basis over the last three weeks. During the week of June 10, we captured 22 potato psyllids across six fields in Canyon County and one psyllid in a field in Payette County. During the week of June 17, we captured one psyllid in each of two fields in Canyon County and three psyllids across two fields in Payette County. We have yet to observe potato psyllids in Twin Falls County after three weeks of monitoring in a few fields. Over the last two weeks, we found psyllids in eight of 12 fields (67 percent) and four of 23 fields (17 percent) being monitored, respectively.

It should be noted that observation of potato psyllids in Idaho during June is not at all unexpected. We typically would find our first psyllids during mid-May.


Oct. 5, 2018

Final 2018 psyllid monitoring update

This week we collected two psyllids from sticky traps in one intense field in Twin Falls County. We only had traps deployed in two fields given that all of the other fields in the monitoring program had been vine killed or harvested. 

One of the psyllids collected last week tested positive for Lso (liberibacter), the bacterium that causes zebra chip. This is only the third psyllid this season to test positive, and this year still has shown the lowest overall incidence in Lso for any season we have been monitoring. Nevertheless, this finding underscores the importance of maintaining an IPM program through the end of the season. We have found that ZC can develop in tubers that were inoculated with Lso-positive psyllids as late as two weeks (and in rare cases one week) before vine kill.

This week’s report concludes the University of Idaho psyllid/Lso monitoring program. We will only provide an update next Friday if we detect Lso in the psyllids collected this week.

Thanks to all of the growers, crop consultants and other industry folks who contributed to this work.

A summary of this year’s results is expected to be presented at the Idaho Association of Plant Protection meeting in Twin Falls in November and at the Idaho Potato Conference.


Sept. 28, 2018

Psyllid update

Psyllids were collected this week on sticky traps in potato in the following counties: Canyon (three fields) and Twin Falls (one field).

This week, we collected nine psyllids from sticky cards (across four intense sites).

Most of the 95 fields that were in the monitoring program have been vine killed or harvested. We had traps deployed in all six of the remaining fields and found psyllids in four of them (66.7 percent). 

All psyllids collected last week tested negative for Lso (liberibacter), the bacterium that causes zebra chip. With only two Lso-positive psyllids found to date, percent incidence has been considerably lower than in all previous years. Nevertheless, we urge growers and crop consultants to maintain their IPM programs. We have found that ZC can develop in tubers that were inoculated with Lso-positive psyllids as late as two weeks (and in rare cases one week) before vine kill.


Sept. 21, 2018

Psyllid update

Psyllids were collected this week on sticky traps in potato in the following counties: Canyon (four fields), Jerome (one field) and Twin Falls (one field).

This week, we collected 40 psyllids from sticky cards (across six intense sites and 0 light sites). We also collected a few eggs and nymphs in leaf samples at two sites in Canyon County; when we have found immature psyllids in the past, they have typically occurred very late in the season as is the case here.

Most of the 95 fields that were in the monitoring program have been vine killed or harvested. We had traps deployed in all 14 of the remaining fields and found psyllids in six of them (43 percent). There are now just a handful of fields being monitored for next week’s report.

All psyllids collected last week tested negative for Lso (liberibacter), the bacterium that causes zebra chip. With only two Lso-positive psyllids found to date, percent incidence has been considerably lower than in all previous years. Nevertheless, we urge growers and crop consultants to maintain their IPM programs. We have found that ZC can develop in tubers that were inoculated with Lso-positive psyllids as late as two weeks (and in rare cases one week) before vine kill.

“Heat maps” of this week’s results will not be made given that the low number of sites remaining tends to result in skewed maps. 


Sept. 14, 2018

Psyllid update

Sept. 14 east heat mapPsyllids were collected this week on sticky traps in potato in the following counties: Canyon (four fields), Twin Falls (two fields) and Cassia (six fields).

This week, we collected 84 psyllids from sticky cards (across seven light sites and five intense sites).

Many of the 95 fields that were in the monitoring program are being vine killed or harvested. We had traps deployed in all 26 of the remaining fields and found psyllids in 12 of these 26 fields (46.2 percent).

All psyllids collected last week tested negative for Lso (liberibacter), the bacterium that causes zebra chip. With only two Lso-positive psyllids found to date, percent incidence is currently considerably lower than in most previous years. Nevertheless, we urge growers and crop consultants to have an IPM program in place.

Sept. 14 west heat map

With so few sites still being monitored this late in the season, it is possible that the heat maps may appear a bit skewed.


Sept. 7, 2018

Psyllid update

Sept. 7 east heat mapPsyllids were collected this week on sticky traps in potato in the following counties: Canyon (two fields), Twin Falls (one field) and Cassia (four fields).

This week, we collected 19 psyllids from sticky cards (across four light sites and three intense sites).

We had traps deployed in all 32 of the 32 fields (100 percent) monitored and found psyllids in seven of the monitored fields (21.8 percent). 63 of the 95 total fields that we were sampling have been vine-killed.

All psyllids collected last week tested negative for Lso (liberibacter), the bacterium that causes zebra chip. With only two Lso-positive psyllids found to date, percent incidence is currently considerably lower than in most previous years. Nevertheless, we urge growers and crop consultants to have an IPM program in place.

Sept. 7 west heat map 


Aug. 31, 2018

Psyllid update

Aug. 31 east heat mapPsyllids were collected this week on sticky traps in potato in the following counties: Canyon (nine fields), Owyhee (two fields), Elmore (one field), Payette (one field), Jerome (one field), Twin Falls (two fields) and Cassia (one field).

This week, we collected 34 psyllids from sticky cards (across 13 light sites and four intense sites).

We had traps deployed in all 89 of the 89 fields (100 percent) monitored this year and found psyllids in 17 of the monitored fields (19.1 percent). Six of the 95 total fields that we were sampling have been vine-killed.

All psyllids collected last week tested negative for Lso (liberibacter), the bacterium that causes zebra chip. With only two Lso-positive psyllids found to date, percent incidence is currently considerably lower than in most previous years. Nevertheless, we urge growers and crop consultants to have an IPM program in place.

Aug. 31 west heat map


Aug. 24, 2018

Psyllid update

heat west map for Aug. 24Psyllids were collected this week on sticky traps in potato in the following counties: Canyon (10 fields), Elmore (one field), Twin Falls (two fields) and Cassia (one field).

This week, we collected 30 psyllids from sticky cards (across nine light sites and five intense sites).

We had traps deployed in all 95 of the 95 fields (100 percent) monitored this year and found psyllids in 14 of the monitored fields (14.7 percent).

All psyllids collected last week tested negative for Lso (liberibacter), the bacterium that causes zebra chip. With only two Lso-positive psyllids found to date, percent incidence is currently considerably lower than in most previous years. Nevertheless, we urge growers and crop consultants to have an IPM program in place.

heat west map for Aug. 24


Aug. 17, 2018

Psyllid update

Heat maps describe predicted psyllid densities across the landscape, based on our trap counts and on predictive models developed over six years of psyllid monitoring in IdahoPsyllids were collected this week on sticky traps in potato in the following counties: Canyon (9 fields), Payette (one field), Twin Falls (three fields), Jerome (one field), Cassia (one field) and Bannock (one field).

This week, we collected 36 psyllids from sticky cards (across 12 light sites and four intense sites).

We had traps deployed in all 95 of the 95 fields (100 percent) monitored this year and found psyllids in 16 of the monitored fields (16.8 percent). However, we are still waiting to receive card data from four sites.

All psyllids collected last week tested negative for Lso (liberibacter), the bacterium that causes zebra chip. With only two Lso-positive psyllids found to date, percent incidence is currently considerably lower than in most previous years. Nevertheless, we urge growers and crop consultants to have an IPM program in place.

Heat maps describe predicted psyllid densities across the landscape, based on our trap counts and on predictive models developed over six years of psyllid monitoring in Idaho 


Aug. 10, 2018

Psyllid update

August 10 east heat map for potato pests

Psyllids were collected this week on sticky traps in potato in the following counties: Canyon (10 fields), Payette (one field), Twin Falls (one field), Jerome (one field), Cassia (three fields), Minidoka (one field), Power (one field) and Oneida (one field).

This week, we collected 36 psyllids from sticky cards (across 15 light sites and four intense sites).

We had traps deployed in all 95 of the 95 fields (100 percent) monitored this year and found psyllids in 19 of the monitored fields (20 percent). However, we are still waiting to receive card data from three sites.

This week we also collected one psyllid from vacuum sampling in one Canyon county field. 

All psyllids collected last week tested negative for Lso (liberibacter), the bacterium that causes zebra chip.

Although psyllid numbers continue to be relatively low thus far this year, we are now starting to see a few more captures in eastern Idaho. With only two Lso-positive psyllids found to date, percent incidence is currently considerably lower than in most previous years.

Nevertheless, we urge growers and crop consultants to have an IPM program in place.

August 10 west heat map for potato pests 


Aug. 3, 2018

Psyllid update

Psyllids were collected this week on sticky traps in potato in the following counties: Canyon (12 fields), Cassia (one field), Jerome (one field), Payette (one field) and Twin Falls (two fields).

This week, we collected 32 psyllids from sticky cards (across 11 light sites and six intense sites).

We had traps deployed in all 96 of the 96 fields (100 percent) monitored this year and found psyllids in 17 of the monitored fields (17.7 percent).

All psyllids collected last week tested negative for Lso (liberibacter), the bacterium that causes zebra chip.

Psyllid numbers continue to be relatively low thus far this year. With only two Lso-positive psyllids found to date, percent incidence is currently lower than what has typically been found during most previous years.

Nevertheless, we urge growers and crop consultants to have an IPM program in place.

Map: moderate (.5-1.50) from Emmett to Marsing, low (.24-.5) from Washington Mill to Triangle and west and none detected (less than .24) right around Melba and everywhere else in southwest Idaho.


July 27, 2018

Psyllid update

Psyllids were collected this week on sticky traps in potato in the following counties: Canyon (11 fields), Cassia (one field), Minidoka (one field), Payette (one field) and Twin Falls (one field).

This week, we collected 30 psyllids from sticky cards (across 13 light sites and two intense sites).

We had traps deployed in 96 of the estimated 96 fields (100 percent) monitored this year and found psyllids in 15 of the monitored fields (19.8 percent). However, we are still waiting to receive cards from 13 sites.

Testing of last week’s psyllids for Lso has been delayed due to the Potato Association of America meeting this week.

Psyllid numbers remain relatively low thus far this year. With two Lso-positive psyllids found to date, percent incidence is similar to what has typically been found during most previous years.

Nevertheless, we urge growers and crop consultants to have an IPM program in place.


July 20, 2018

Psyllid update 

Psyllids were collected this week on sticky traps in potato in the following counties: Canyon (10 fields), Cassia (three fields), Elmore (one field), Minidoka (two fields), Payette (one field) and Twin Falls (two fields).

This week, we collected 29 psyllids from sticky cards (20 light sites and nine intense sites).

We had traps deployed in 93 of the estimated 96 fields (96 percent) that will be monitored this year and found psyllids in 19 of the monitored fields (20.4 percent).

All psyllids collected last week tested negative for Lso (liberibacter), the bacterium that causes zebra chip.

Psyllid numbers remain relatively low thus far this year. With two Lso-positive psyllids found to date, percent incidence is similar to what has typically been found during most previous years.

Nevertheless, we urge growers and crop consultants to have an IPM program in place.


July 13, 2018

Second Lso-positive potato psyllid this year

Psyllids were collected this week on sticky traps in potato in the following counties: Canyon (eight fields), Cassia (three fields), Owyhee (one field), Jerome (two fields) and Twin Falls (three fields).

This week, we collected 31 psyllids from sticky cards (13 light sites and four intense sites). 

We had traps deployed in 92 of the estimated 96 fields (96 percent) that will be monitored this year and found psyllids in 17 of the monitored fields (18.5 percent).

One psyllid collected last week in Canyon County tested positive for Lso (liberibacter), the bacterium that causes zebra chip.

Psyllid numbers remain relatively low thus far this year. With two Lso-positive psyllids found to date, percent incidence is similar to what has typically been found during most previous years.

Nevertheless, we urge growers and crop consultants to have an IPM program in place.


July 6, 2018

First Lso-positive potato psyllid

Psyllids were collected this week on sticky traps in potato in the following counties: Canyon (four fields), Owyhee (two fields), Gooding (one field) and Twin Falls (one field).

This week, we collected 13 psyllids from sticky cards (seven light sites and one intense site).

We had traps deployed in 93 of the estimated 97 fields (95 percent) that will be monitored this year and found psyllids in eight of the monitored fields (8.6 percent). However, we are still waiting to receive cards from eight sites.

One psyllid collected last week in Canyon County tested positive for Lso (liberibacter), the bacterium that causes zebra chip.


June 29, 2018

Psyllid abundance remains relatively low

Psyllids were collected this week on sticky traps in potato in the following counties: Canyon (six fields), Owyhee (one field) and Twin Falls (two fields).

This week, we collected 16 psyllids from sticky cards (eight light sites and one intense site). 

We had traps deployed in 85 of the estimated 97 fields (87 percent) that will be monitored this year and found psyllids in 9 of the monitored fields (10.5 percent). However, we are still waiting to receive cards from four sites.

All psyllids collected last week tested negative for Lso (liberibacter), the bacterium that causes zebra chip.

Thus far, psyllid abundance has been relatively low this year; however, potato psyllid abundance typically increases during July through August.


June 22, 2018

A few more psyllids found in Treasure and Magic Valleys

Psyllids were collected this week on sticky traps in potato in the following counties: Canyon (three fields), Jerome (one field) and Twin Falls (one field).

This week, we collected 10 psyllid from sticky cards (three light sites and two intense sites).

We had traps deployed in 85 of the estimated 97 fields (87 percent) that will be monitored this year and found psyllids in five of the monitored fields (5.8 percent). However, we are still waiting to receive cards from 19 sites.

All psyllids collected last week tested negative for Lso (liberibacter), the bacterium that causes zebra chip.


June 15, 2018

First potato psyllid found in Magic Valley

Psyllids were collected this week on sticky traps in potato in the following counties: Canyon (three fields), Owyhee (one field) and Twin Falls (one field).

This week, we collected six psyllid from sticky cards (five light sites).

We had traps deployed in 75 of the estimated 85 fields (88 percent) that will be monitored this year and found psyllids in five of the monitored fields (5.8 percent).

The psyllid collected last week tested negative for Lso (liberibacter), the bacterium that causes zebra chip.


June 8, 2018

Another psyllid found in Treasure Valley; none in Magic Valley

One potato psyllid was collected on a sticky trap in potato in the following county: Canyon (one field).

This week, we collected one psyllid from sticky cards (one light site).

We had traps deployed in 50 of the estimated 89 fields (56 percent) that will be monitored this year and found one psyllid in one of the monitored fields (2 percent).

The psyllid collected last week tested negative for Lso (liberibacter), the bacterium that causes zebra chip.


June 1, 2018

First potato psyllid found in Idaho potato fields this season

One potato psyllid was collected on a sticky trap in potato in the following county: Canyon (one field).

This week, we collected one psyllid from sticky cards (one light site).

We had traps deployed in 50 of the estimated 88 fields (57 percent) that will be monitored this year and found one psyllid in one of the monitored fields (1.13 percent).


2018 Potato psyllid monitoring program underway in Idaho

The University of Idaho, in collaboration with Miller Research and several crop consultants across the state will continue our monitoring program for potato psyllids, zebra chip and liberibacter (Lso), the bacterium that causes zebra chip. The monitoring program covers commercial potato fields throughout southern Idaho and currently is funded in part by USDA and generous in-kind contributions by our collaborators.

The first deployment of sticky cards occurred last week in 17 Treasure Valley sites and 21 Magic Valley sites. Next week we expect to initiate sampling in eight and 17 additional fields in the treasure and magic valleys, respectively.

This week we collected our first sticky cards of the season from potato fields. No potato psyllids were found in potato fields this week.

More details on the program will be forthcoming as we continue to ramp up sampling efforts. We hope to maintain a monitoring program at a level similar to recent years, but the breadth of the program this year will depend on funding that is still pending.


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