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Eastern New York Field Crops Pest Report, 2004
This is a seasonal scouting report giving growers in the Eastern New York area information on the presence of agricultural pests. The report is written by Ken Wise, IPM Extension Area Educator for Livestock and Field Crops.
Alfalfa Weevil Eggs Present
Do you know the number of growing degree-days in your region
More Crown and Root Rot Reports
There have been more reports of crown and root rot in Eastern NYS. Remember there are several kinds of rots and symptoms look similar. For more information on crown and root rot check out our on-line guide: Diseases of Alfalfa (Wilts and Rots) Management Guide
Downy Mildew on Alfalfa
During a TAg meeting in Lewis County we discovered many of the plants had downy mildew. Symptoms of downy mildew are leaves become blotched and are light green or yellow. Many times young leaflets can become distorted. Often a dark purplish-gray fungal mat covers the underside of the leaves. This disease is common early in the spring. For more information view are on-line management guide: IPM for Alfalfa Diseases: Leaf Spots
Potato Leafhopper Found in the North Country
While Jennifer Beckman (Lewis County) was conducting a TAg meeting (May 11) this week she discovered one lone potato leafhopper in the sweep net. If potato leafhoppers are that far north already most likely you will find them in many other locations around the state. Do you know what potato leafhopper looks like? Remember adults are bright lime green, 1/8 inch long and can fly. Potato leafhopper nymphs are yellowish-green and look similar to the adult but do not have wings.
Black Cutworm Management
Black Cutworm larvae vary in color from light gray to black with a pale brown to black head. Larvae have a greasy, shiny appearance with coarse granules present over their body. During the day larvae burrow into the soil next to the corn plant. These larvae curl into a C shape when disturbed. Symptoms of damage are leaf feeding, irregular holes in stem, notched and cut or missing plants. No-till fields and those with a lot of grass weeds are at particular risk to black cutworm. Monitor fields to find cutworm larvae when they are less than 1/2 inch long. If there are sufficient numbers and damage present, an insecticide could be justified. Treat only the affected area and a 20 to 40-foot border around the infestation. Rarely does a whole field need to be treated for cutworm. Larger cutworm larvae, greater than 1/2 inch long, are much more difficult to control. If the majority of cutworm larvae are 1/2 inch long or larger their damage is already done. These large larvae are also more tolerant of insecticides, reducing the effectiveness and economic viability of this option.
Check out our on-line publication, Black Cutworm in Field Corn Management Guide 912K pdf file
Weed Emergence in Eastern NYS
NYS IPM has access to emergence predictions models for the State on a few important weeds. Weed emergence models can help with monitoring weeds in the fields, thus when to expect to see them. The following are the ranges in percent weed emergences in Eastern NYS from North to South.
North Country Oneida/Herkimer C. Lower Hudson Valley
Large Crabgrass 5% 20% 50%
Pigweed 5% 10% 30%
Giant Foxtail 20% 35% 70%
Common Lambsquarter 20% 35% 70%
Velvetleaf 20% 30% 80%
Yellow Foxtail 20% 40% 80%
Common Ragweed 70% 85% 100%
Birds in Corn
Thanks to: Jennifer Beckman (Lewis County), Jeff Miller (Oneida County), Julie Stavisky (NYS IPM) and Keith Waldron (NYS IPM) for helping with this week’s report!