Soybean
Early instar corn earworm are now being reported in Kent and Sussex counties. At 77 °F, it takes earworms approximately 2-3 days to hatch and 6 days before they reach the third instar. First and second instar mortality can be pretty high. Below is a photo of an early instar earworm that is still more of an orange color with black microspines and tubercles. Often in soybean I observe green color morphs which have a green head. They curl into a C-shape or will bite aggressively when picked up, as opposed to green cloverworm which wiggle vigorously and do not curl or bite.
Early instar corn earworm
Pay attention to the NCSU corn earworm threshold calculator (https://www.ces.ncsu.edu/wp-content/uploads/2017/08/CEW-calculator-v0.006.html) and to other pests that may be active in the field when considering control. Just ball parking some figures for a 13 dollar control cost and a 13.50 value for soybean, an approximate EIL is around 2.5 worms in 15 sweeps. HOWEVER, if you enter a soybean value of 10 dollars, the EIL does not change. Enter a lower value, say 8 dollars per bushel and the EIL changes by almost 0.75 worms. Given how an EIL is calculated, this would indicate that a more accurate EIL estimate for 13.50 worms may be closer to 1.5 to 2 worms per 15 sweeps for say a 13 dollar control cost.
Pyrethroids are not guaranteed to provide good efficacy. I have had spray trials in which they did very well across the board and spray trials in which efficacy was around 70% or lower. They are cheaper, but if there are enough worms present and you do not have great efficacy, then it is possible that you will not remove enough worms to drop the population below a threshold level. Besiege is one of the more common insecticides considered and has a pyrethroid which will pick up bean leaf beetles and stink bugs. A few other insecticides worth considering include Vantacor, Denim, Blackhawk, Intrepid Edge, and Steward.
Soybean loopers are active throughout North Carolina and Virignia’s coastal plain. While it is not certain that loopers will migrate up in large numbers, it does occasionally happen, especially in double crop soybean fields. In 2020, we had a spray trial in a field in which looper numbers increased from 0.8 loopers per 30 sweeps on September 2 to 47 loopers per 30 sweeps on September 24. Warrior and Baythroid resulted in even higher looper counts. Besiege, Coragen, and Prevathon (now Vantacor) resulted in about 20 loopers in 30 sweeps and Denim resulted in 3. Also in 2020, we dropped a looper trial in that field adjacent to our earworm trial. Steward and the highest Hero rate provided excellent control. I caution against pyrethroids such as Hero, they have a reputation of flaring loopers in other states. Orthene tank mixed with pyrethroids can provide excellent worm and stink bug control, but can also setup a field for a looper outbreak.
Denim was recently labeled for use in soybean against worm pests only at 8 -12 fl oz per acre. In our 2020 spray trial, it resulted in good reduction of CEW. It does have a ‘Danger’ signal word on its label so pay special attention to label precautions.
Sorghum
Continue scouting flowering to milk stage sorghum for earworm and fall armyworm. Refer to Texas A&M’s sorghum headworm threshold calculator: https://extensionentomology.tamu.edu/sorghum-headworm-calculator/. In addition to the above guidance on soybean, we had good results with carbaryl. Also, sorghum webworm is present in low numbers. Its threshold is more than twice that of fall armyworm/corn earworm.
Turf
Scout for fall armyworm and black cutworm. Damage can appear very quickly. We are seeing some fall armyworm activity in various crops, but have not heard any indication that this year’s population is as great as last year’s. Nevertheless, they should be scouted for. Black cutworm last year were present in some turf fields at high enough levels to warrant a treatment. Both pests can be controlled with pyrethroids.