Joanne Whalen, Extension IPM Specialist; jwhalen@udel.edu
NOTE – Be sure to check BLT catches in your area for corn borer and corn earworm catches — we are starting to see a significant increase in trap catches. Unfortunately, the web page will not be updated until next week but you can get updates this Saturday by calling the Crop Pest Hotline (in state: 800-345-7544; out of state: 302-831-8851).
Cabbage
Continue to sample for cabbage looper, diamondback larvae, fall armyworm and Harlequin bug. Although the pyrethroids will provide control of Harlequin bugs, they are not effective on diamondback in our area. So be sure to scout and select control options based on the complex of insects present in the field.
Lima Beans
Continue to scout for stinkbugs, lygus bugs and corn earworm. With the increase in corn earworm moth catches, moths can be readily found laying eggs in fields. Be sure to sample for corn earworm larvae as soon as pin pods are present. A treatment will be needed if you find one corn earworm larvae per 6 ft of row.
Peppers
At this time of year, corn borer, corn earworm, beet armyworm and fall armyworm are all potential problems in peppers. So be sure to select the material that will control the complex of insects present in the field. Be sure to check local moth catches in your area by calling the Crop Pest Hotline (instate: 800-345-7544; out of state: 302-831-8851). We are also starting to see aphid and mite populations increasing, especially in fields where pyrethroids have been used on a weekly basis. Treatments for both of these pests will need to be applied before populations explode.
Snap Beans
With the increase in trap catches, you will need to consider a treatment for both corn borer and corn earworm. Sprays are needed at the bud and pin stages on processing beans for corn borer and corn earworm control at this time. As a reminder, if you are using Orthene (acephate) for corn borer control, it will not provide effective corn earworm control in processing snap beans. You will need to combine Orthene with a corn earworm material (e.g. a pyrethroid) or use a material that will control both insect pests. To help decide on the spray interval between the pin stage and harvest for processing snap beans, you will need to call the Crop Pest Hotline Saturday, Aug 21 for the most recent trap catches in your area or check the web site next week for updated catches (http://ag.udel.edu/extension/IPM/traps/latestblt.html and http://ag.udel.edu/extension/IPM/thresh/snapbeanecbthresh.html).
Spinach
As the earliest planted spinach emerges from the ground, be sure to watch for webworms and beet armyworms. Both moths are active at this time and controls need to be applied when worms are small and before they have moved deep into the hearts of the plants. Also, remember that both insects can produce webbing on the plants. Generally, at least 2 applications are needed to achieve control of webworms and beet armyworm.
Sweet Corn
As corn earworm trap catches continue to increase, be sure that a spray is applied as soon as ear shanks are visible on plants. If fall armyworms are present in the whorl, you may need multiple whorl sprays for this insect before the ear shank spray to achieve effective control. Once fields are silking, you will need to check both blacklight and pheromone trap catches for silk spray schedules since the spray schedules can quickly change. Saturday, Aug 21 you can call the Crop Pest Hotline (in state: 800-345-7544; out of state: 302-831-8851) for updated trap catches. At this time of year, you will need to combine a fall armyworm material with a pyrethroid for the first 2-3 silk sprays for fall armyworm control. Be sure to check all labels for days to harvest and maximum amount allowed per acre.