|->Home > fieldcrops > tag > pestrpt > pestrpt04
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 11, 2004
I was monitored re-growth
on a few alfalfa fields and found small 2nd and 3rd
instar alfalfa weevil larvae. Tip feeding by alfalfa weevil larvae
was 20 to 35 percent. Remember, that the action threshold for alfalfa
weevil on 2nd cutting is 50 percent tip feeding with
small larvae present. While the fields were not at threshold there
were many small alfalfa weevil larvae. On top of that was an infestation
of potato leafhopper that was not present the week before. While
they were not at an action threshold, potato leafhopper can increase
in numbers quickly with warm weather. Having two stresses on alfalfa
re-growth could have the potential to cause yield and forage quality
losses. In fields like these you should monitor them closely. For
management information check our on-line IPM guides: IPM for Potato Leafhopper
in Alfalfa and IPM for Alfalfa
Every year a few good observant scouts ask me, “Why have western corn rootworm adults appeared in June.” Recently, I spotted a few of these western corn rootworm imposters in my garden. Do you know who these imposters are? “Striped Cucumber Beetle.” Striped Cucumber Beetle and Western Corn Rootworm look similar but are two different species of insects.
Beetle, Acalymma vittatum
Western Corn Rootworm, Diabrotica
Learn more about
the differences between Western Corn Rootworm and Striped Cucumber
Ground Beetles Look for Prey in Corn Fields
This week, I have seen several ground beetles in corn fields. Ground beetles are very good predators of several insect pests in corn and other crops. Generally, we think of them as those big black beetles we find in the garden or under rocks. There are more that 20,000 of species of ground beetles in the world ranging in size from very small to large. The adult beetles can appear in a fascinating array of colors, textures and spots. Many studies have shown that smaller fields with grassy margins can promote ground beetle predation. Both the soil-dwelling larvae and above-ground adults feed on several different kinds of insect pests. Currently, some entomologists in the country are researching on how much predation occurs on corn rootworm by ground beetle larvae. For a few good pictures and general information on ground beetles you can view this web-site: Ground Beetles
Yellow Nutsedge in Fields
There were large
infestations of Yellow
Nutsedge in several cornfields at the SUNY Cobleskill farm this
week. So is yellow nutsedge a grass? No, it is a sedge!
Many different organisms cause seed rot and seedling blights. Most of these organisms are soil-borne and a few are seed-borne. Most seed rots and seedling blights proliferate in poorly drained, cold (less than 58 degrees) and wet soils.
Seed Rot: Many times the infected seed will not germinate. If the seed does germinated the radicle will become infected and rot. The rot can be tan, brown, gray or black and the seed or radicle will appear wet and mushy. Some of the organisms that infect seed are Pythium, Fusarium, and Rhizoctonia.
Seedling blight: It is difficult to determine which pathogen causes seedling blight in any one field. Many times it can be a complex of Pythium, Rhizoctonia and Phytophtora. Pythium can cause the seedlings to have a wet, rotted appearance, while Phytophtora generally appears as a dry, dark rot on the roots. Sunken, reddish-brown lesions on the hypocotyls is most likely a Rhizoctonia infection. The Rhizoctonia lesions are small when they first appear. As these lesions grow they can girdle the stem, causing the soybean plant to die. If the Rhizoctonia infected seedlings do not kick the bucket the infection will weaken the stem and may cause the plant to lodge after the pods form.
More on soybean diseases next week!
Cereal Leaf Beetle has Been Spotted in Eastern NYS!
Jeff Miller in Oneida County discovered cereal leaf beetle in wheat fields this week. Please check the last two issues of the pest report for identification, monitoring and thresholds for cereal leaf beetle.
Thanks to: Jeff Miller (Oneida County), Keith Waldron
(NYS IPM) and Julie Stavisky (NYS IPM) for contributing to this