Phone calls and reports have slowed considerably over the past 10-14 days. Most of the cotton is no longer susceptible to insects and some is beginning to open. We have some areas that have gotten good rainfall over the past week; however, many areas are very dry and need rain badly. Soybeans have been the focus of most calls this week, with stink bugs and caterpillars being the main concerns.
Soybeans
Stink Bugs
For the most part, early planted (April) beans are safe from
most all of our insect pests, including stink bugs. Our threshold prior to R6
is 4 bugs per 25 sweeps. Once R6 (beans touching inside pods of upper 4 nodes)
is reached, we double the threshold to 8 bugs per 25 sweeps for 7-10 days
(R6.5-pod and pod wall beginning to turn mature color) then we can terminate
insecticide applications.
We have observed green, southern green, brown and brown
marmorated stink bug adults and nymphs in fields across the state. A high
labeled rate of a pyrethroid will do a good job killing any of these in
soybeans and save the crop from economic damage if threshold populations are found.
Caterpillars
Our soybean looper and corn earworm (podworm) trap counts
have been up significantly the past couple of weeks. We have had more acres infested
and treated for podworms this year than we have had in the past 5 or more years.
Our threshold for podworms is around 6 per 25 sweeps.
Right now, the velvetbean caterpillar seems to be the dominant
species in the mix thus far, which is good because they can easily be managed
with most labeled insecticides. I would, however, be a little cautious with
pyrethroids given their ability to flare loopers and the big moth flight we’ve
experienced this past couple of weeks. The threshold for defoliators is to treat
at 20% defoliation from R1-R6 and 30% defoliation after R6 for 7-10 days.
Alternatively, treat when 38 VBC or 19 SBL are caught per 25 sweeps.
As always, if we can ever be of any help, or if you would
like to provide input on the situation in your area, please don’t hesitate to
reach out (Scott Graham: 662-809-3368; Ron Smith: 334-332-9501). To stay
up-to-date on the Alabama insect situation, subscribe to the Alabama Cotton
Shorts Newsletter,
Alabama Crops Report Newsletter,
and the Syngenta Pest Patrol Hotline.
