High Populations Of Insects In The East

potato field

Many species that overwinter in Pennsylvania apparently have done so with high survival rates. For example, we’ve seen very strong populations of several species of maggots, cucumber beetles, and asparagus beetle in April and May. However, many of our pests tend not to overwinter, but arrive as long distant migrants. We can now confirm that the long-distant migrants listed below have also been reported in May.

At our research farm in Centre County, we have found a few corn fields with substantial black cutworm damage. Black cutworms are primarily pests of corn, but they can also attack tomato, pepper, and eggplant. These caterpillars are active at night, but were easy to find with a trowel by digging up the cut seedling. Presence of the black, greasy looking caterpillars verifies the source of damage, which can be difficult to diagnose in some cases, particularly in slug infested fields.

To hedge against any surprises, growers and field personnel would be wise to scout fields for cutting damage, and apply rescue treatments if larvae are small and the economic threshold is exceeded. Females lay eggs in dead vegetation on the soil surface and in weeds, where moisture is high. Young larvae feed on the leaves of emerging corn, whereas the older larvae cut the plant off at the base or bore into the plant. In sweet corn, check each planting weekly during the spike through the five-leaf stage. Check for small irregular holes in the leaves, and missing or cut plants.

If cutworms are present, examine 10 sets of 20 plants throughout the field and record the percent of cut or damaged plants. Look under clods of dirt and vegetation and the bases of plants for the larvae; if you see the larvae, record the average size and the number per 100 plants. In sweet corn during the two-leaf stages, apply a treatment if more than 10% of the plants show fresh signs of feeding. At the three to four-leaf stages apply treatment at a 5% level.

Also, use your judgment based on stand count. If you are at the minimum stand count, you may need immediate treatment, whereas more feeding can be tolerated if the stand is heavier than needed. During drier conditions, treatments may be less effective because cutworms may be feeding below the soil surface. In these cases, rotary hoeing or cultivation, as well as using higher spray volumes, may help increase the chances of contacting the insects with the pesticide.

After four or five weeks, the larvae pupate in the soil. Two more generations may occur, but damage does not tend to occur from later generations, so no treatment is needed if the population is finishing its larval feeding stages and pupating. Full grown larvae are about 1.75 inches in length and although feeding damage increases with larval size, feeding will stop when they pupate. For more details on black cutworm see: www.ento.psu.edu/extension/factsheets/black_cutworm.htm.

True armyworms are also active. These caterpillars can cause damage to small grains and corn, but tend to be most problematic in corn planted before a small grain cover crop was completely dead. Be sure to scout for damage from this pest because, true to its name, populations can generate quickly and march through fields causing extensive damage — in corn characteristic defoliation leaves just the midrib remaining- For details, go to http://ento.psu.edu/extension/factsheets/armyworm.

This is a year where you need to be scouting your fields and be prepared for earlier-than-usual pest pressure.

Leave a Reply

Featured Stories
Crop Protection
June 25, 2017
New Approach Suggests Closer-Proximity Lures Help Increase Catches
Research shows single-trap locations are not as effective as those kept close together. Read More
girl on smartphone
GenNext Growers
June 24, 2017
Find the Food Safety Apps That Are Right for You
There are a lot of choices available for growers. We’ve sifted through them to help figure out which ones will best suit you. Read More
Apples & Pears
June 23, 2017
Take Advantage of Technology to Help Manage Diseases, Pest Pressure
Expert farm advisers provide several options for apple orchard management decisions. Read More
Mobile technology farming
Citrus
June 22, 2017
Technology Boom Boosting Farm Life to a New Level [Opinion]
Whether it is human genetics or genetics applied to plants, knowledge is growing at a dizzying pace. Read More
Crop Protection
June 21, 2017
Certis Bolsters Biopesticide Business Portfolio with Acquisition
Addition of LAM International to allow for expansion of product development. Read More
Food Safety
June 21, 2017
Organization Seeks Winegrape Exemption Produce Safety Rule
California Association of Winegrape Growers says because winegrapes are grown for processing, they should be exempt from produce safety rule. Read More
Crop Protection
June 21, 2017
Early-Season Scouting Tips for Sweet Corn Growers
Black cutworm and true armyworm have been caught in relatively high numbers across the Midwest, including Michigan. Learn more about determining risk and scouting in your sweet corn plantings. Read More
honeybee with varroa mite
Citrus
June 21, 2017
Study Suggests Modern Beekeeping Gives Varroa Mites Ideal Conditions to Spread
Parasite has adapted, thrived with colonies in modern hives. Read More
More Vegetables
June 21, 2017
Variety Specs | Production Tips: Pumpkin ‘Bayhorse Gold’ from Rupp Seeds
Each month, American Vegetable Grower® will offer growing tips on specific varieties, supplied by the breeder or distributor. This month, Read More
Citrus
June 21, 2017
Storm Runoff May Recharge Aquifers and Your Crops
A new study hints that tapping into storm water during dry years does more than increase water table levels. Read More
Citrus greening and psyllids
Insect & Disease Update
June 21, 2017
First Case of Deadly Citrus Disease Confirmed in Alabama
State agriculture officials taking action to assess and stop the spread of HLB.  Read More
Florida orange juice label close-up
Citrus
June 21, 2017
Help Consumers Read past Negative Headlines About Orange Juice
When it comes to this liquid sunshine, there are plenty of positives to point out. Read More
Cucurbit leaf crumple virus
Cucurbits
June 20, 2017
Take Caution to Curb Cucurbit Leaf Crumple Virus
Learn how to identify, the survival and spread, as well as management methods for this disease. Read More
Berries
June 20, 2017
Don’t Be Fooled By Rust in Your Brambles
Knowing whether you have orange rust disease or cane leaf rust is important for proper control methods. Read More
Up-close shot of a hops plant during the 2016 Florida Ag Expo
Farm Management
June 20, 2017
5 Alternative Crops Florida Farmers Should Consider
Here’s a look at new selections being vetted that might have a place in fields around the Sunshine State. Read More
The Latest
Crop Protection
June 25, 2017
New Approach Suggests Closer-Proximity L…
Research shows single-trap locations are not as effective as those kept close together. Read More
GenNext Growers
June 24, 2017
Find the Food Safety Apps That Are Right…
There are a lot of choices available for growers. We’ve sifted through them to help figure out which ones will best suit you. Read More
Apples & Pears
June 23, 2017
Take Advantage of Technology to Help Man…
Expert farm advisers provide several options for apple orchard management decisions. Read More
Citrus
June 22, 2017
Technology Boom Boosting Farm Life to a …
Whether it is human genetics or genetics applied to plants, knowledge is growing at a dizzying pace. Read More
Crop Protection
June 21, 2017
Certis Bolsters Biopesticide Business Po…
Addition of LAM International to allow for expansion of product development. Read More
Food Safety
June 21, 2017
Organization Seeks Winegrape Exemption P…
California Association of Winegrape Growers says because winegrapes are grown for processing, they should be exempt from produce safety rule. Read More
Crop Protection
June 21, 2017
Early-Season Scouting Tips for Sweet Cor…
Black cutworm and true armyworm have been caught in relatively high numbers across the Midwest, including Michigan. Learn more about determining risk and scouting in your sweet corn plantings. Read More
Citrus
June 21, 2017
Study Suggests Modern Beekeeping Gives V…
Parasite has adapted, thrived with colonies in modern hives. Read More
More Vegetables
June 21, 2017
Variety Specs | Production Tips: Pumpkin…
Each month, American Vegetable Grower® will offer growing tips on specific varieties, supplied by the breeder or distributor. This month, Read More
Citrus
June 21, 2017
Storm Runoff May Recharge Aquifers and Y…
A new study hints that tapping into storm water during dry years does more than increase water table levels. Read More
Insect & Disease Update
June 21, 2017
First Case of Deadly Citrus Disease Conf…
State agriculture officials taking action to assess and stop the spread of HLB.  Read More
Citrus
June 21, 2017
Help Consumers Read past Negative Headli…
When it comes to this liquid sunshine, there are plenty of positives to point out. Read More
Cucurbits
June 20, 2017
Take Caution to Curb Cucurbit Leaf Crump…
Learn how to identify, the survival and spread, as well as management methods for this disease. Read More
Berries
June 20, 2017
Don’t Be Fooled By Rust in Your Brambles
Knowing whether you have orange rust disease or cane leaf rust is important for proper control methods. Read More
Farm Management
June 20, 2017
5 Alternative Crops Florida Farmers Shou…
Here’s a look at new selections being vetted that might have a place in fields around the Sunshine State. Read More
Citrus
June 19, 2017
$9M in Grants Allocated to Address Ag Wa…
Projects that focus on drought stress, flooding, water quality, and postharvest use are among awardees. Read More
Citrus
June 19, 2017
How to Get the Most out of Growing Citru…
2017 Citrus Achievement Award winner Ed Pines provides insider information on unique production method. Read More
Varieties & Rootstocks
June 19, 2017
Florida Growers Seeking to Strike Citrus…
Varieties showing HLB tolerance giving growers hope, sparking more questions. Read More