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Edited by Tom Kuhar, Assistant Professor, Dept. of Entomology, Virginia Tech
Greetings crop producers, researchers, extension personnel, and crop consultants,
Weather summary for week ending April 23, 2004 - Painter, VA
James T. Custis (Farm Manager, ESAREC)
It was a warm and dry week on the Eastern Shore. No precipitation this week. Most days ranged from 70 to 80 degrees F and nights were in the 60's. In short, it was a very productive week for working the land.
Blacklight and Pheromone Insect Traps
Jack Speese & Tom Kuhar (ESAREC).
Many insect species commenced spring activity this week, but there was relatively little "pest" insect activity recorded at our blacklight traps in Cheriton and Painter, VA. We did pick up a couple early-flying European corn borer moths.
Cereal leaf beetle update
Ames Herbert (Virginia Tech Tidewater AREC, Suffolk, VA)
I am late getting this short note out regarding cereal leaf beetle (CLB) in wheat. After searching wheat fields for nearly 5 weeks, we are finally finding a few fields with adult beetles and eggs. A large portion of the eggs are dark orange which means they will be hatching within a few hours (they will have hatched by the time you read this). The outbreak is considerably later than normal because of the late spring. Late spring cool temperatures delayed adult activity and egg laying. Based on what we are finding in many of the fields we have searched and based on the input from several of you, CLB populations seem to be very spotty - that is, they are absent in many fields and present in just a few. However, we have found at least one field with a large population - an average of almost 40 eggs per row foot of wheat which is almost twice the economic threshold. They are following the known pattern, that is, CLB populations are most abundant in fields with sparse wheat foliage, cover-crop plantings, or late planted fields.
What do we recommend? Scout fields to find the threshold populations (25 eggs/small larvae per 100 stems). Tank mix insecticides with other treatments (fungicides) if they are going to be applied. If applications are for CLB populations that are mostly in the egg stage, use the high rate of Mustang Max (4.0 oz/acre) or 2.0 oz of Warrior T. Based on our past field tests, it will take this higher rate of Mustang Max to provide the same level of residual control as the Warrior T, that is needed to last the rest of the infestation period. If you wait to treat until the population is older (all eggs hatched and only larvae present), then lower rates of Mustang Max will work well. We have not tested Mustang Max below the 2.24 oz/acre rate, although it is labeled as low as 1.76 oz/acre.
Will CLB populations continue to build? Good question. With this hotter weather, we think the CLB infestation will progress quickly. Most adults should already be out and most eggs should be deposited within the next few days. Larvae will be hatching very soon and leaf feeding will begin. We don't expect a lot of new or additional adults to emerge, so what you see over the next week to ten days should be it for the season. Find and treat those fields that are at or near the economic threshold and save your money/insecticide on those fields with fewer than threshold numbers.
Aphids in small grain crops in Northampton Co.
Information provided by Harvey Belote (Windy's Flying Service)
We are seeing a lot of aphids in small grains on the lower end of the Eastern Shore.
(Added comments from Tom Kuhar from the VA Coop. Ext. Field Crops Pest Management Guide)
Aphid control during the spring is not often necessary, but may be needed if infestations are threatening and the weather is unusually mild. Treatment is suggested if aphid counts exceed 150 per linear foot of row and there is little natural enemy activity such as presence of aphid mummies, ladybeetles, nabid bugs, syrphid fly larvae, etc..
Insecticide treatment of intensive management wheat in the spring in Virginia is suggested based on the following:
100 aphids/ row ft on plants 3-6 inches
200 aphids/row ft on plants 7-10 inches
300 aphids/row ft on plants 11+ inches tall
At heading, 20-25 aphids/ grain head
New formulation of chlorpyrifos insecticide - Lorsban 75WG
Information provided by: Paul J. David, Field Development Representative, Gowan Company
Lorsban 75WG is a new formulation of chlorpyrifos insecticide that will be marketed by Gowan. This formulation is superior to the old 50W formulation, which has been phased out. The 75WG is a very unique formulation which has been described as an encapsulated "dry EC". In the coming months, we will be refining this label to incorporate many of the old 50W specific uses. Dow AgroSciences has tested the 75WG formulation extensively. Field trials have indicated performance equal to or better than that obtained with the 4E / 50W formulations. Potential for phytotoxicity with the 75WG on sensitive crops is significantly less than that observed with the 4E formulation. Rainfastness is significantly greater for the 75WG than either the 4E or 50W formulations. Another added benefit of the 75WG formulation is very little odor. Field reports have indicated a dramatic difference between the new 75WG and the older formulations. This should be of high value to growers interested in using a Lorsban product where the traditional odor has been an issue.
Correction to the Danitol 2.4 EC listing in the Commercial Vegetable Recommendations manual
Info. provided by John Cranmer (Valent)
Please note in the Commercial Vegetable Recommendations book VCE Publication No. 456-420, that the restricted re-entry interval (REI) for Danitol 2.4 EC is listed incorrectly for all cucurbits (including cucumbers, muskmelons, pumpkins, squash and watermelons). The correct REI is 24 hours.
Request for information
Tom Kuhar (ESAREC)
If you have any crop pest information that might benefit Virginia growers, please send it to me in an e-mail, and I'll include it in the Crop Pest Advisory. Thank you.
Thomas P. Kuhar
Assistant Professor
Department of Entomology
Eastern Shore Agricultural Research & Extension Center
Virginia Polytechnic Institute & State University
33446 Research Drive
Painter, VA 23420
E-mail: tkuhar@vt.edu
Tel: 757-414-0724
FAX: 757-414-0730
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