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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.

June 15, 2004

Eastern New York Cornell University Weed Day

Date:  Wednesday, JULY 7.

Where: CORNELL/VALATIE RESEARCH FARM, Valatie, NY (State Farm Road off Route 9 just north of Valatie)
Time: 9:30 a.m. Registration, 10:00 - 12:00 p.m. Field Crop Weed Control
Note: CCA and DEC Credits have been requested
Why Come: You can learn and see the newest strategies for controlling weeds in field corn!

Alfalfa

Potato Leafhopper on the Rise: What are the Management Options?

The number of potato leafhoppers in fields are increasing in Eastern NYS. There were also both potato leafhopper adults and nymphs in the alfalfa. Do you know what to do if a field reaches an action threshold for potato leafhopper in alfalfa?

Option 1: Early Harvest

You can harvest the alfalfa early to control potato leafhoppers if the field is within a week to ten days of a scheduled harvest. By harvesting the alfalfa early prevent potato leafhopper from reaching infestation levels that can cause yield and quality loss to the forage. Make sure that the whole field is harvested at the same time. If a field is not clean harvested then the alfalfa that has not been cut will serve as a refuge for potato leafhoppers and can re-infest; thus severely damaging alfalfa re-growth.

Option 2: Use an Insecticide

To protect yield and health of new seedings and established alfalfa, insecticide control can be warranted when a field is not within a week of harvest. For selection of an insecticide consult the current issue of Cornell Guide for Integrated Field Crop Management. Remember to read the label and be aware of blooms, bees and the days until harvest restrictions.

Option 3: Plant Potato Leafhopper Resistant Alfalfa

A third option for control is planting potato leafhopper resistant alfalfa. Obviously, it is a little late for this season’s crop but something to consider for future seedings. Research has shown that potato leafhopper resistant alfalfa is consistently higher in quality than susceptible alfalfa varieties with or without potato leafhopper pressure. PLH resistant varieties yields are comparable and generally better than susceptible varieties when PLH are present. A bonus benefit is that currently available alfalfa varieties with PLH resistance have come down in price over the past several years.

For management information check our on-line IPM guides: IPM for Potato Leafhopper in Alfalfa

Alfalfa Weevil Larvae Still Small

There are still small larvae in re-growth of alfalfa. Tip feeding in the fields I have been monitoring is 10 to 30 percent. Remember to check windrow areas as these potentially may have a higher AW population due to the consolidation of alfalfa in the hay swath. Also recall that the action threshold for alfalfa weevil on 2nd cutting is 50 percent tip feeding with small larvae present. For management information check our on-line IPM guides: IPM for Alfalfa Weevil.

Beneficial Organisms in Alfalfa: Green Lacewing

Green lacewings are one of the coolest insects around. I have observed a few in my sweep net this season in alfalfa fields and by the porch light at night. Adults feed during the evening on nectar, pollen, and aphid honeydew. Larvae are very active predators of aphids and other small insects in many agricultural crops. Adults are light green and long, slender antennae, golden eyes and have large lace-like wings that are 1/2 to 1/3 inches long. Larva are called antlions, and look like little green-gray or brownish alligators. Antlions have sickle-shaped jaws, that penetrate the prey and injects a paralyzing venom, then sucks out the victims body fluids. The larvae will reach about a1/2" long before they pupate.

Field Corn
Maize Billbug damage
Have you ever seen 2 or 3 identical holes side by side across a leaf when the corn is 2 to 6 inches tall? You may be familiar with cutworms as a possibility. Another less well known and much harder to find insect is the maize billbug. This small (2/5-3/5 inch), nocturnal, reddish brown to black weevil has the characteristic weevil beak-like snout. This minor insect pest (maize billbug) drills through the main stem of the plant. Corn, grasses and sedges are preferred billbug foods. When the plant grows and the leaf unrolls it leaves 2 or 3 holes side by side. Bill bug populations can be associated with high yellow nutsedge infestations. Maize billbug rarely causes economic damage to the corn crop. Watch for potential damage to the corns growing point. (See: Maize Billbug, Sphenophorus maidis (Chittenden), Curculionidae, COLEOPTERA http://ipm.ncsu.edu/AG271/corn_sorghum/maize_billbug.html

Velvetleaf Causes Yield Reduction: Critical Weed Control Timing!

While monitoring corn fields this week I saw an abundance of velvetleaf. Research from Purdue University suggests that just 1 velvetleaf plant per row foot if not controlled in first 4 to 6 weeks after planting can reduce yields by 25 percent. Twelve plants per row root can reduce yields by 57 percent. This means the earlier you can control them the better the yield. Research by our own Janice Degni and Russ Hahn has shown that velvetleaf yield impacts on corn were also highly affected by soil moisture ­ the more droughty the soil conditions the more the impact. We are still looking for better weather prediction data to help us with developing this threshold. For management information check our on-line IPM guides: Weeds in Corn Management Guide

Corn Rootworm and Fireflies

Keith Waldron reports observing fireflies while visiting Washington DC last week. In our area, firefly sightings are associated with the estimated hatching time for corn rootworm larvae. Have you seen fireflies in your neighborhood? It won’t be long now….

Soybeans
Sclerotinia stem rot/white mold
As soybean fields start growing and canopies begin to close keep on the lookout for sclerotinia stem rot/white mold caused by Sclerotinia sclerotiorum. Field symptoms include isolated patches of stunted, yellow or lodged plants. A fluffy white mycelium can be found on the lower stem and surrounding ground. Small black pellet-like sclerotia may also be present on or in affected stems or on the mycelium. Affected stems will be soft and mushy at infection site. For management information check our on-line IPM guides: Soybean Pests (Diseases and Weeds) Management Guide

Small Grains

How to Recognize Scab (Fusarium head blight) on Wheat

One of the most devastating diseases of wheat is Scab or also called “Fusarium head blight.” This disease infects the grain head at flowering. The disease builds up in corn, wheat and other grain residues. During the day the spores are carried up into the atmosphere and at night settle out across the landscape. If it rains at flowering and spores are present there is a good chance the grain will become infected with the disease. The first symptoms of Fusarium head blight occur shortly after flowering. Diseased wheat heads exhibit premature bleaching as the pathogen progresses. One or more spikelets located in the top, middle, or bottom of the head may be bleached. Over time, the premature bleaching of the spikelets may progress throughout the entire head. If the environment is warm and moist, aggregations of light pink/salmon colored spores may appear on the rachis and glumes of individual spikelets. Later in the season, bluish- black spherical bodies may appear on the surface of affected spikelets. As symptoms progress, the fungus colonizes the developing grain causing it to shrink and wrinkle inside the head. Often, the infected kernels have a rough, wilted appearance, ranging in color from pink, soft-gray, to light-brown.

Think Stored Grain Pests, NOW!

It is time to start CLEANING your grain bins. Sanitation is the key to keeping insect pests out of your stored grains. Wheat harvest is not as far off as you may think so knowing what you need to do is important. The following is a step by step method for IPM in stored grain:

1.   Clean grain handing equipment (augers, combines, wagons, scoops, and trucks).

2.   Clean inside the grain bin (remember to clean under the false floor). Mice, moths, weevils and        much more can survive under the false floor.

3.   Clean around the outside of the grain bin. Remove all weeds, spilled grain and debris 6 to 10 feet from around the grain bin. This will remove all habitats that can support a grain bin pest problem.

4.   Seal all cracks and crevices. Cracks are prime locations for insects to enter grain bins.

5.   Cover fans when they are not being used. Insects can enter the grain bin this way also.

6.   Use a registered sanitizing insecticide spray in and around the structure after cleaning.

7.   Never store new grain with old grain.

8.   Dry the grain bin before adding new grain. Insect pests need moisture to survive.

9.   Level the surface after filling the grain bin. Moisture accumulates in a grain peak.   Microbial activity in the wet area will heat up and attract secondary insect pests.

10. Do not fill grain bin all the way to the top. Leave a few feet for aeration.

11. Aerate the grain to at least the ambient temperature. The hotter the grain gets the faster insect   pests can develop. Stored grain insect pests development slows when the temperature falls    below 500 F.

12. Monitor grain for insect pests every 20 days from spring till fall and every 30 days in the winter.  

13. If you discover an infestation of insect pests you may consider an insecticide application. Select   a NYS registered product for your stored grain. READ THE LABEL.

14. Keep areas around grain bins mowed to limit rodent hiding places.

Common Insect Pest of Stored Grain

  • Granary weevil

  • Saw tooth grain beetle

  • Red flower beetle

  • Larger cabinet beetle

  • Lesser grain borer

  • Rice weevil

  • Indian-meal moth

  • Flat grain beetle

  • Angoumois grain moth

  • Confused flower beetle

(See: IPM in Kentucky Farm Stored Grain, http://www.ca.uky.edu/entweb/storage/open.html, IPM Tactics for On-Farm Stored Grain http://www.aces.edu/pubs/docs/A/ANR-1126/ANR-1126.pdf

and Improve Stored Grain Through IPM, http://www.okstate.edu/ag/impact/impact21.htm

Thanks to: Jeff Miller (Oneida County), Nate Herendeen (Northwest NYS Dairy, Livestock and Field Crop Team) Keith Waldron (NYS IPM) and Julie Stavisky (NYS IPM) for contributing to this week's report.


Cheers
Ken Wise