Crop, Disease & Insect Update Fulton Co

Soybeans have improve in appearance and yield outlook over the past month. The dry weather has allowed the plants to root down, nodulation to provide nitrogen and some of the damaged plants to recover. During my August 6&7 trip through the county, the bean stage of growth ranged from R1 to R6 with 84% of the beans in R4-R6 stage. R4 is the full pod stage where a 3/4 inch pod is on one of the four upper nodes. R6 is full seed where a pod containing a green seed fills the cavity at one of the four upper nodes.
Soybean Insects-From and insect standpoint Japanese beetle are the most prevalent insect, some bean leaf beetle were found and a few grasshopper. For these defoliating insect plants in R4-R5 can tolerate 15% defoliation and R6-R8 (Maturity) 25% defoliation when looking at the entire plant.
Soybean Aphid were found in 6 of 44 fields but at very low levels of less than 1 per plant on average. The highest single plant counts were 10 aphids per plant. Fields that had aphids also had Asian Lady Beetles active on plants with higher populations. The threshold for insecticide treatment is still 250 aphids per plant plus with the advancing growth stage most field will not require treatment. Instead what we are seeing is the normal off year build up of populations in the fall. Monitoring fields in flowering stages or double crop would be suggested. Another scouting focus would be field that were treated with insecticides during the week of July 28th. Fields treated this week would have had beneficial insects killed which may allow for the rapid build up of Soybean Aphid is those fields depending on the residual length of the insecticide used and the growth stage of the plants.
Disease is generally limited to brown spot on the lower leaves but some downy mildew is beginning.

Corn has all progressed into the reproductive stages. Some corn is still pollinating and is in the blister stage. A majority of the corn is the R3 or milk stage which is very comparable to what we eat as sweet corn in appearance. A few fields show aborted or unpollinated kernels and ear tips not filled to the end. Diseases are still generally very low. The 2008-25 issue of C.O.R.N. has two articles worth looking at Assessing the Success of Pollination in Corn and Evidence of Drought and Heat Stress Appearing in Corn Fields You can now find grayleaf spot and rust is still present but has generally not spread very far. Insects are low as well a few corn rootworm beetles and some evidence of European Corn Borer can be seen.

Wheat while 2008 crop is in the books 2009 planning has already begun. The 2008 Wheat Performance Trial Information is available on line and an article on Wheat Fungicide Seed Treatment can be found in the C.O.R.N. newsletter 2008-25 edition. If you are planning to use your own seed please take a close look at this for recommendation for wheat scab and glume blotch (Stagonospora nodorum) control since both were seen in the area with the 2008 crop.