There have been several reports of caterpillars and at least two queries about the lesser corn stalk borer over the past week. Let’s discuss some of the moth activity and season flux in pest activity common in peanuts during July and August.
We have included a graph below showing season-long data indicating trends in insect activity based on sticky wing pheromone trap, which are small highly-portable traps. We have combined trap data with actual crop scouting information for added benefit to producers. Be careful when you compare our insect trap numbers to other methods that may capture a higher number of moths.
For control recommendations, refer to the Alabama Peanut IPM Guide.
Corn earworms and tobacco budworms: This year we have experienced a strong and early-season tobacco budworm moth activity compared to other years. Usually corn earworms (CEW) are plenty in pheromone traps and caterpillars in the crop, but we couldn’t find very many caterpillars in peanuts at Headland and Brewton even after intense scouting. There were more armyworms and loopers that anything else.
Both CEW and tobacco budworms seem to be in the third or fourth overlapping generations, and may intensify in coming weeks. Mississippi and Georgia are also reporting spikes in moth activity/trap catches around row crops. Refer to the control methods carefully since TBW is difficult to control with many conventional pyrethroid insecticides.
Loopers: These are the typical mid-season caterpillars and we may be detecting the second or third generations in our trap depending on location. Cabbage looper (CL) moth activity is four times as high as the soybean looper (SL) moth activity. In the peanut plots in Brewton, we have seen a low number of both species with feeding on young terminal leaves. CL moth numbers have been very high in pheromone traps at Headland for the past two weeks – so producers need to watch out for excessive leaf feeding.
Armyworms: These are interesting pests as they have a broad host-range that includes grassy plants. We usually see a mid- to late-season shift of armyworm moths from hay fields/pastures to peanuts and vegetable crops – this is happening right now. This is the reason why fall armyworm (FAW) moth numbers show lag in May and June along with sharp spikes in July and August; moth numbers were highest in southwest AL. Beet armyworm (BAW) moth numbers average about 10 moths per trap with peak activity seen in Central AL.
Lesser cornstalk borer: With the prevailing dry conditions, expect high lesser cornstalk borer (LCB) activity in soil and sample the soil near peanut pods real closely. Moth numbers ranged from 80 to 173 per trap across the peanut production areas of AL – this is a very high level of moth activity and in sandy areas, LCB larvae may be seen in tunnels near the developing pods.
We have seen some silken tubes in soil at Headland and have initiated test treatments ahead of an outbreak. Irrigation is one of the best way to reduce LCB feeding on peanuts and promote rapid development of the pods.