July 30, 2004      No. 21

Current Insect Conditions:

Pea aphids and cowpea aphids being reported in alfalfa fields in Southwest Kansas. Cowpea aphids are dark-colored aphids generally feed near the tips of infested stems. Pea aphids are large green aphids that usually feed along the stems. For pea aphids host plant resistance can reduce aphid damage so check to see if alfalfa variety is suppose to have resistance or not. Early cutting may solve the problem when heavy infestations develop close to cutting time. On 10-inch tall alfalfa, treatment generally is not needed until nearly 50 aphids per stem are present. On 20-inch tall alfalfa, twice as many aphids per stem would be required before treatment is justified. Thresholds for cowpea aphids have not been established and populations are often too spotty to justify field wide treatments. For treatment information on the pea aphid see: http://www.oznet.ksu.edu/entomology/extension/InsectInfo/Alfalfa/Pea%20Aphid.html  and for the cowpea aphid see: http://www.oznet.ksu.edu/entomology/extension/InsectInfo/Alfalfa/Cowpea%20Aphid.html 

Blister beetles have been reported in some alfalfa fields in central Kansas. This should be a reminder to review some of the basics of blister beetle management. 1. Don’t promise to sell blister beetle free hay, there is no way to guarantee hay to be free of blister beetles. 2. Insecticides are not recommended for blister beetle control because by the time the harvest interval is over the field could be re-infested. 3. Scouting is difficult because swarms can be very isolated and there is no way to take enough samples to insure finding them. 4. Management practices such as watching for and cutting around swarms when swathing, not using a conditioner, and avoiding driving over windrows can reduce the chance of hay containing blister beetles but not eliminate the possibility. For more information on Blister Beetles see http://www.oznet.ksu.edu/entomology/extension/InsectInfo/Alfalfa/Blister%20Beetles.html and http://www.oznet.ksu.edu/library/ENTML2/MF959.PDF 

 According to historical information we should be in the middle of corn borer oviposition this week, but so far populations have been low. But if you have non-Bt corn planted now would be the time to be checking for egg masses. Information on European corn borer can be found at: http://www.oznet.ksu.edu/entomology/extension/InsectInfo/Corn/European%20Corn%20Borer.html  and for Southwestern corn borer at: http://www.oznet.ksu.edu/entomology/extension/InsectInfo/Corn/Southwestern%20Corn%20Borer.html 

Spider mite numbers in corn are low in most fields, but a few fields are being reported with moderate to heavy numbers of mites so fields should continue to be checked for the next couple of weeks. However there is a good chance that many fields should get by with no treatments this year.

Corn rootworm beetles continue to be reported in some fields, but populations are probably on the decline in most areas.

Corn leaf aphids are being found in sorghum, but few greenbugs. Surprisingly with all of the rain there are also still reports of chinch bugs in central and eastern Kansas.

Sorghum headworms and cotton bollworms (aka the corn earworms) are being reported in Oklahoma. A reminder that we will need to be on the lookout this pest as sorghum begins to head and cotton begins to set bolls.

And last but not least if you have sunflowers that are beginning to bloom you will want to be on the alert for head moth. Early reports indicate that populations don’t appear to be as heavy as last year, but there still may be enough to warrant treatment. Information on head moth management can be found at: http://www.oznet.ksu.edu/library/ENTML2/MF814.PDF 

Phil Sloderbeck

False Wireworms:

Now is probably the time to begin thinking about potential problems in winter wheat fields this fall from false wireworms. Several calls have been received about large numbers of false wireworm beetles around homes, and businesses the last few weeks, which is an indication that they are probably abundant in some fields.

If large numbers of beetles are present now then it could be an indication that larvae could be a concern this fall. There are different species of false wireworm beetles and they vary widely in size and shape but most are black or gray in color, some have a reddish stripe down the middle of their backs.

False wireworm beetles are most common in the western two thirds of Kansas. Their wing covers are fused and thus the beetles are flightless. The larvae of these beetles usually do not attack growing plants, but feed on seed wheat between the time of planting and germination. They are most commonly a problem in continuous wheat.

Growers that notice significant numbers of these beetles this summer might want to consider a seed treatment this fall. Planter box seed treatments containing lindane are labeled for false wireworm control. Follow label directions on rates, method of application and safety precautions. Do not feed treated seed or contaminate grain not being used for seed. Note: Imidacloprid (Gaucho) and Thiamethoxam (Cruiser) are not labeled for false wireworm control and for whatever reason; reportedly do not adequately control these pests. Thus, while these seed treatments are popular choices for many pests, if false wireworms are the targeted pest, lindane seed treatments may be a better choice.

The good news is that false wireworm larvae prefer dry soil and damage is most evident when dry conditions delay seed germination. Thus it may be the large numbers of beetles we are seeing now may be more of an indication of the dry conditions we had last year that a signal of problems this fall, but the weather between now and planting time will really determine the potential for these insects to be a pest this fall.

Phil Sloderbeck

Soybean Aphids:

Very low densities (1 small, wingless aphid per 10 plants) of soybean aphids are still being detected in one field in Riley County.  Also, low densities have been reported from Marshall County.  Please let us know if you find these aphids in your county.

Potato Leafhoppers:

We're continuing to find potato leafhoppers during sweep net sampling of alfalfa. Samples have ranged from 3-17 per 10 sweeps.  This is a little less than last year but populations still need to be monitored as densities will probably continue to increase.  Consult your Alfalfa Insect Management Guide (2004) for treatment thresholds and insecticide recommendations.

Jeff Whitworth

Weekly Report from the Kansas State University Insect Diagnostic Laboratory:

The following samples were submitted to the Insect Diagnostic Laboratory from July 21 through July 29, 2004:

    7-21-2004, Pottawatomie County: Vein Pocket Gall in Oak.
    7-21-2004, Miami County: Aphids on Grapes.
    7-27-2004, Johnson County: Great Golden Digger Wasp in field.
    7-27-2004, Logan County: Various Arthropods on Spruce.
    7-27-2004, Nemaha County: Erineum Mite on Maple.
    7-27-2004, Edwards County: Mites on Willow.
    7-28-2004, Reno County: Brown Recluse and Wolf Spiders from home.
    7-28-2004, Riley County: Funnel Web Spider from home.
    7-28-2004, Riley County: Winged Ants in home.
    7-29-2004, Riley County: Dung Flies from field.

If there any questions regarding these samples or about the identification of any arthropod please contact the Insect Diagnostician at 785-532-4739 or at bbrown@oznet.ksu.edu. 

Bobby Brown

Brand names appearing in this publication are for product identification purposes only. No endorsement is intended, nor is criticism implied of similar products not mentioned.

Sincerely,

Phil Sloderbeck                                                                          Bobby Brown
Kansas State University                                                              Entomology Diagnostician
Southwest Research and Extension Center   
Garden City

Jeff Whitworth       
Extension Specialist   
Entomology   (Crops)