Joanne Whalen, Extension IPM Specialist; jwhalen@udel.edu
Melons
Continue to scout all melons for aphids, cucumber beetles, and spider mites. As a general guideline, a treatment should be considered when you find 20-30% of the plants infested with 1-2 mites per leaf. Be sure to check all labels for rates, precautions and restrictions, especially as they apply to pollinators. There have also been reports of insect feeding on drip tape resulting in a significant number of leaks in the tape. If you are experiencing problems, please be sure to contact Joanne Whalen (jwhalen@udel.edu) so we can try to evaluate the extent of the problem.
Peppers
As soon as the first flowers can be found, be sure to consider a corn borer treatment. Depending on local corn borer trap catches, sprays should be applied on a 7 to 10-day schedule once pepper fruit is ¼ – ½ inch in diameter. Be sure to check local moth catches in your area by calling the Crop Pest Hotline (in state: 1-800-345-7544; out of state: 302-831-8851) or visiting our website at (http://ag.udel.edu/extension/IPM/traps/latestblt.html). You will also need to consider a treatment for pepper maggot. Be sure to watch carefully for beet armyworm larvae since they can quickly defoliate plants.
Potatoes
Continue to scout fields for Colorado potato beetle (CPB), aphids and leafhoppers. Controls will be needed for green peach aphids if you find 2 aphids per leaf during bloom and 4 aphids per leaf post bloom. This threshold increases to 10 per leaf at 2 weeks from vine death/kill. If melon aphids are found, the threshold should be reduced by half.
Snap Beans
Continue to scout for leafhopper and thrips activity in seedling stage beans. Sprays will be needed at the bud and pin stages on processing beans for corn borer control. Acephate can be used at the bud and pin stages on processing beans but remember it has a 14-day wait until harvest. Once corn earworm trap catches start to increase again, you will also need to select a product that controls corn earworm as well. Additional sprays may be needed after the pin spray on processing beans. Since trap catches can change quickly, be sure to check our website for the most recent trap catches and information on how to use this data to make a treatment decision in processing snap beans after bloom (http://ag.udel.edu/extension/IPM/traps/latestblt.html
and http://ag.udel.edu/extension/IPM/thresh/snapbeanecbthresh.html). Once pins are present on fresh market snap beans and corn borer trap catches are above 2 per night, a 7 to 10-day schedule should be maintained for corn borer control.
Sweet Corn
Continue to sample all fields from the whorl through pre-tassel stage for corn borers and corn earworms. We have found the first fall armyworm larvae in whorl stage sweet corn. A treatment should be considered when 12-15% of the plants are infested. Since fall armyworm feeds deep in the whorls, sprays should be directed into the whorls and multiple applications are often needed to achieve control
The first silk sprays will be needed for corn earworm as soon as ear shanks are visible. Be sure to check both black light and pheromone trap catches for silk spray schedules since the spray schedules can quickly change. Trap catches are generally updated on Tuesday and Friday mornings (http://ag.udel.edu/extension/IPM/traps/latestblt.html
and http://ag.udel.edu/extension/IPM/thresh/silkspraythresh.html). You can also call the Crop Pest Hotline (in state: 1-800-345-7544; out of state: 302-831-8851).