James Johnson & Monica Wiebe
JUNE 23, 2000                                                                          Vol. 15 No. 4

RUSSIAN WHEAT APHIDS
     We surveyed the Rockland and Arbon and Mink Creek areas. In Rockland out of the 5 fields surveyed all 5 had Russian Wheat Aphid (RWA). In the Arbon area 3 out of 5 had RWA.  The Mink Creek area had several fields of spring wheat at least 3-4 inches in height. Most all fields had RWA in it.   The threshold for RWA is;

Season Plant growth stage Threshold
     
Fall Seedlings (l tiller) 10% plants infested
Fall Larger plants Treat if plants are stressed or there is danger of winter kill
Spring (Winter grain) green up to appearance of 1st   node 5% plants with reproducing populations and fresh damage
Spring (Winter grain)   appearance of  1st node to head emergence 10% tillers infested
Spring (Spring grain) Emergence to head emergence 10% of tillers infested
Spring Head emergence to soft dough.  (After the soft dough stage, insecticide treatment will have little to no benefit) Treat only if heavy populations (i.e. more than 20 aphid per plant) develop on 10-20% of flag leaves or stems
a/   After the soft dough stage, insecticide treatment will have little to no benefit.

Other Cereal Aphids
    So far this year the aphid collections from the traps have been very low. This does not mean they are not in the fields. They may just be happy on the plants their on.
    Funded by the University of Idaho Agricultural Experiment Stations and the Wheat & Barley Commissions.

IDAHO 
APHID   DATA

Samples collected JUNE 9 & 16, 2000

Cereal Others

Total

Suction Trap Location

 Russian Wheat Aphid Green Bug Bird Cherry Oat Aphid English Grain Aphid Rose Grass Aphid Corn Leaf Aphid Apple Grain Aphid Green Peach Aphid Potato Aphid Pea Aphid Spotted Alfalfa Aphid Bean Aphid (All Aphids)
Moscow - - - - 1
 - - - - 1
2		 - - 21
14
Lewiston - - 1
 - 7
5		 1
 - - - 1
1		 1
 - 24
8
Parma - -

1		 4
7		 - - - - - - - 6
11
Picabo - - - - - - - - - - - - NS
8
Kimberly - - - - -   - - - 3
 - - 6
0
Burley - -
1		 - - - - - - 1
 - - 2
2
Aberdeen - -
1		 - - - - - - 1
 - - 7
1
Rockland - - - - - - - - - 1
1		 -
2		 - 2
5
Arbon - - - - 1
 - - - - 1
1		 1
 - 7
3
Soda Springs - - 2
 - - 1
 - - - 4
 - - 11
2
Ririe - - - - - - - - - - - - 0
0
Tetonia - - - - - - - - - - - - 1
0