Have You Read The Most Recent Issue of Ohio Soybean News?
July 7, 2015 Ohio Soybean Council
Dr. Andy Michel offered some great tips for managing pests in 2015:
1. COLD WEATHER: The cold weather last winter did not necessarily knock out all soybean insects. Some, like soybean aphids, are quite capable of surviving outdoors as eggs or even indoors, like the brown marmorated stink bug.
2. SLUGS: Not technically insects, they are one of the most devastating early-season pests. A rainy spring will favor slug development.
3. EARLY-SEASON BEAN LEAF BEETLE: Bean leaf beetles are common early season defoliators, although economic damage is rare. If your field emerges early and your soybeans are stressed, you may need a rescue treatment to prevent damage.
4. KUDZU BUG: This invasive pest is commonly found in the southern U.S. and is on the march toward Ohio. It may appear this year in vegetative stage of soybeans.
5. TWOSPOTTED SPIDER MITES: Some weather models predict a drier than normal summer which increases the risk of spider mites. Monitoring for yellowing or bronzing of soybean leaves on field edges is the best way to catch a mite problem early.
6. APHIDS: Usually we see soybean aphids in odd numbered years and 2015 may be no different. We have observed soybean aphids on their overwintering host in the fall and will be checking in the spring for early emerging colonies.
7. BEES AND POLLINATORS: Several important, general pollinators, including honeybees, can be found in soybean when flowering. There are restrictions and guidelines from the Ohio Department of Agriculture to follow when spraying insecticides on flowering soybean to prevent any off-target impacts.
8. LATE SEASON BEAN LEAF BEETLE: Pod feeding by bean leaf beetle is more serious, as it only takes 10% of pods on a plant with damage to cause significant yield loss. Careful monitoring is needed during pod stage, all the way up to R6 to prevent yield loss.
9. STINK BUGS: These pod and seed feeders are becoming more and more common. Several species are known, and can cause shriveled and wrinkled beans which impacts yield and seed quality. Check soybean from July-September for the presence of stink bugs.
10. PRE-HARVEST INTERVALS: If a late season insecticide application is necessary to limit bean leaf beetle or stink bug damage, double check the pre-harvest interval. This is the number of days to wait before harvest can be made after the application.
Mark Loux offered some top tips for fall herbicide application:
1. The best time to spray is any time between after harvest and Thanksgiving. Dr. Mark Loux from The Ohio State University observes that he has even applied into late December and still had good weed control. Once hard freezes start to occur, there is usually a substantial change change in the condition of certain weeds, such as dandelion and thistle, that renders them less sensitive to herbicides.
2. Regardless of even heavy residue left on the fields, herbicides still seem to work. However, it doesn’t hurt to wait a while after harvest to let the residue settle down and the weeds to poke through.
3. Don’t overthink fall weed control or spend a ton of money. Keep in mind the primary goal is control of already-emerged weeds. This is hard to accomplish with a single herbicide, but there are a number of relatively low-cost, two-way mixtures that easily achieve this goal.
4. There is no advantage to using residual herbicides because almost all of them deteriorate over the winter and fail to provide any control of spring-emerging weeds. Research has repeatedly shown that applying residual herbicides in the fall to get control in the spring is a waste of money.
5. It doesn’t take a lot of herbicide to control weeds in the fall, just the right ones. Consider that fall treatments should comprise no more than about 25 percent of your total herbicide budget, and it can often be accomplished for even less than that.
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