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Eastern New York Field Crops Pest Report, 2003

For 4/30/03:

Hello Field Croppers:
Once again we start on the road of reporting pest problems in field crops throughout Eastern New York.

Alfalfa

Alfalfa looked very good and was 3 to 5 inches tall at the SUNY Cobleskill farm on Friday, April 25th. 

Alfalfa Weevil: April 15th of last year I saw many adult alfalfa weevils in fields at SUNY Cobleskill. So far this season I have not yet seen one adult weevil. Do you think all of the snow killed them this winter? Most likely not and they will soon invade alfalfa fields. The big question is "how do we determine if alfalfa weevil is causing economic loses in the fields?" Below is the procedure for monitoring alfalfa weevil:

Monitor alfalfa weevil weekly from mid to late-April through June. Because weevil populations can build up over the life of the alfalfa stand, monitoring fields that are two or more years in production is critical to determine infestation levels. Start weekly field sampling in fields at about 350 degree-days (base temperature 48F0) which is about mid to late April.

  • Pick 50 alfalfa stems at random throughout the field.

  • Look for the small "shot holes" in the leaves that indicate that larvae are feeding.

  • Record the percentage of alfalfa stems that show the "shot hole" feeding damage in the top 3 inches of the canopy.

Before the first cutting, if 40% of the stem tips show feeding damage, you are at the "action threshold".

Check out our on-line publication, IPM for Alfalfa Weevil. 1.2 Mb pdf file

Field Corn

Be Prepared! Seed Corn Maggot May Find Your Fields!
Seed corn maggot (SCM) is an insect pest that feeds on large seeded crops like corn and soybean. An adult female fly searches for moist soil cracks, high organic matter, decomposing plant material, fields with manure and germinating seeds in which to lay their eggs early in the spring. Maggots hatch from the eggs and feed by burrowing into germinating seeds. These maggots are tapered, legless, appear to be headless, pale yellowish-white, and reach a length of about ‰. Symptoms of SCM damage may show up as skips in the corn rows or as "snake heads" i.e. seedlings without cotyledons. Proper diagnosis requires some digging in the gaps within a row to check for seeds and on seed health. Prevention is the key to control this insect pest by using an insecticide planter box seed treatment or pretreated seed.

For more information on SCM management check out Early Season Insect Pests of Corn, 1Mb pdf file

Early Season Corn Diseases
Once again, prevention is the key to control early season corn diseases!!!!!
By using a fungicide planter box treatment it will help prevent corn seed from many different early season diseases. Sound planting practices, such as use of certified seed, good seed bed preparation, good seed soil contact, and appropriate planting depth, help promote stand establishment and help avoid seedling blights and emergence diseases.

For more information on early season disease management visit our web page on Field Corn Diseases.

Worms in Field Corn and Other Crops

Is it a bird or a plane? No, it's true armyworm and black cutworm coming to fields near you! (Or NOT?) Check your next issue of the Eastern New York Field Crops Pest Report.

Cheers,
Ken Wise