Scouting a must for 2011 soybean aphids
Results of fall scouting of soybean aphid indicate that soybean growers may face some level of soybean aphid populations this summer.
“We expect Ohio to continue its two-year cycle of very few if any aphids being found followed by low to moderate to even high populations somewhere in the state,” said Ohio State University Extension entomologist Ron Hammond with the Ohio Agricultural Research and Development Center.
Hammond and his colleagues scouted for eggs on buckthorn, the pest’s overwintering host, and found some eggs, although not as many as anticipated. However, given the observations recorded of aphids on buckthorn in other Midwest states, entomologist believe Ohio will likely see more aphids next year than in 2010.
“It is impossible to predict which regions of Ohio, if any, will experience outbreak conditions,” said Hammond, explaining that factors ranging from the weather to natural predators all play a role in the severity of aphid populations. “At this time, growers should just be aware that scouting for aphids will probably be more important next summer during July and early August.”
The soybean aphid, first discovered in Ohio in 2001, is a sapsucker whose voracious appetite can greatly damage untreated soybean fields. It also has been known to transmit a host of viruses, including soybean mosaic virus, soybean dwarf virus, and alfalfa mosaic virus not only in soybean but also in a number of vegetable crops.
Soybean aphid populations this past summer were practically nonexistent, although entomologists did see a build-up of aphids on late-maturing soybeans. However, the late aphid build-up was expected and is a contributing factor to finding eggs on buckthorn this fall.
For growers, the best way to manage the soybean aphid is to educate themselves on the insect, know when to scout, and to carefully time foliar insecticide applications if treatments are warranted. The economic threshold of aphids is 250 insects per plant with a rising population.
"We continue to recommend taking an Integrated Pest Management (IPM) approach to aphid management. While seed treatments will control early season aphid populations, they will not have any impact in mid-summer when aphids arrive in large numbers," said Hammond. "We will recommend scouting soybeans from early July through August, and using the threshold with a rising population density to determine the need for treatment."