Watch for Spider Mites in Dry Areas

Spider mite stippling damage in soybean (bugwood.org)

By: Andy Michel and Kelley Tilmon, OSU Extension

Hot, dry weather encourages certain pests in field crops, in particular spider mites in soybean and occasionally corn.  Spider mites are a sporadic problem that most often occurs in August, but infestations in July are possible with sustained periods of hot, dry weather like some parts of Ohio are experiencing.  Crop scouts in areas that have not received rain recently should be on the lookout for this problem; spider mites are easy to miss in early stages and can build quickly.

Look for light-colored stippling damage which is easier to spot than the mites themselves.  In areas with heavy stippling you can confirm the presence of mites by tapping vegetation over a black piece of construction paper.  [Many sources will say to use white paper; but insider tip:  they are actually easier to see against a dark background].  The mites will look like specks of dust that move.

Stippling is common in the lower canopy even in non-outbreak situations.  When the stippling extends up into the middle canopy and is common, treatment is recommended.  We do not recommend edge treatments for this particular pest.  Make the decision for the whole field.  Most pyrethroid products with the exception of bifenthrin are not effective against spider mites and may even flare them.  Lorsban and generics have been popular choices against mites but may be less available now.  Check the field five days after application for resurgence because these products do not kill mite eggs.

There are specific miticide products that are particularly effective because they also kill mite eggs, eliminating the next generation.  Two such products are abamectin (Agri-Mek SC), labeled for use on soybeans, and etoxazole (Zeal), labeled for use on corn and soybeans.

A resurgence of moisture will go a long way to reducing spider mite populations.  Mites are particularly susceptible to fungal insect/mite killing pathogens which are favored by moist conditions (one of the reasons dry weather encourages mite outbreaks).

 

 

 

Double Crop Soybean Recommendations

By: Laura Lindsey, OSU Extension

As small grains are harvested across the state, here are some management considerations for double-crop soybean production:

Relative Maturity. Relative maturity (RM) has little effect on yield when soybeans are planted during the first three weeks of May. However, the effect of RM can be larger for late planting. When planting soybean late, the latest maturing variety that will reach physiological maturity before the first killing frost is recommended (Table 1). This is to allow the soybean plants to grow vegetatively as long as possible to produce nodes where pods can form before vegetative growth is slowed due to flowering and pod formation.

Table 1. Recommended relative maturity (RM) ranges for soybean varieties planted in June and July in northern, central, and southern Ohio. Continue reading

Soybean Vegetative Growth Stages- VC vs V1

By: Laura Lindsay, OSU Extension

Across the state, soybean growth and development is variable, ranging from early vegetative stages to flowering. However, there has been some confusion regarding the identification of the VC and V1 growth stages. This confusion is mostly due to two definitions of V1…that actually mean the same thing. The Fehr and Caviness Method (1977) is based on the number of nodes that have a fully developed leaf, whereas Pederson (2009) focuses more on leaf unrolling so that the leaf edges are no longer touching. The VC definition for both methods is the same, but the differences start to appear between the methods at V1. Continue reading

Recommendations for Soybeans Planted in June

By: Laura Lindsey, OSU Extension

While progress is way ahead of last year, soybean planting is spilling into June. (According to USDA NASS, 53% of soybean acreage was planted by May 24, 2020. Last year, at the same time, only 11% of soybean acreage was planted.) As planting continues into June, farmers may want to consider adjusting their cultural practices:

Row spacing. Soybean planted in narrow rows (7.5 or 15-inch row width) generally yields higher than soybean planted in wide rows (30-inch). The row spacing for June-planted soybeans should be 7.5 to 15 inches, if possible. Continue reading

Rhizobia Inoculant Following the 2019 Season

By: Laura Lindsey and Stephanie Karhoff, OSU Extension

Following wet weather conditions and fallow fields, some producers are wondering if they need to inoculate their soybean seed with Rhizobia.

Soybean plants have a symbiotic relationship with bacteria in which the bacteria fix nitrogen from the atmosphere into a plant-available form of nitrogen. In soybean, nitrogen fixation is associated with Bradyrhizobium japonicum (commonly referred to as just Rhizobia). Generally, fields with a history of soybean production have an adequate population density of Bradyrhizobium japonicum. In our research trials, we have measured a yield increase of approximately 1.5 to 2.0 bu/acre when soybean seed is inoculated and the field has a history of soybean production. Continue reading

Sorting Out the Soybean Herbicide Resistance Traits

By: Mark Loux, OSU Extension

The world of soybean herbicide resistance traits has gotten more complex over the past several years.  The good news is that we have new options for control of herbicide-resistant weeds, although it can be a little difficult to sort out which one is best for a given situation and whether the possible downsides of certain traits are tolerable.  The following is a quick rundown of what’s available and some things to consider when selecting seed.  Continue reading

Stink Bug Management In Non-Uniform Crop Stages

By: Kelley Tilmon and Andy Michel, Ohio State University Extension

With all the planting difficulties in 2019 there are soybeans in a much greater variety of growth stages than usual this summer. What does this mean for stink bug management? First, it means that different fields will be in the danger zone at different times. Stink bugs feed on developing pods and seeds, with the potential for damage beginning in R3 and R4-R5 being prime damage time, with damage potential still lingering in early R6. Continue reading

Considerations for Using Soybeans as a Cover Crop

By: Laura Lindsey, OSU Extension Soybean Specialist

From the USDA RMA website (https://www.rma.usda.gov/News-Room/Frequently-Asked-Questions/Prevented-Planting-Flooding):

“Q. Can I plant a cover crop of the same crop I was prevented from planting? Or in other words, can I use the seed I have on hand (corn, soybeans, wheat) to plant a cover crop as long as it’s at a lower seeded rate that qualifies for cover crop?

  1. Yes. An acceptable cover crop must be generally recognized by agricultural experts as agronomically sound for the area for erosion control or other purposes related to conservation or soil improvement is planted at the recommended seeding rate, etc. The cover crop may be the same crop prevented from planting and may still retain eligibility for a prevented planting payment. The cover crop planted cannot be used for harvest as seed or grain.”

Soybean is an acceptable cover crop as it is agronomically sound for the area for erosion control or other purposes related to conservation or soil improvement. Continue reading

Recommendations for Late Planted Soybeans

By: Laura Lindsay, OSU Extension Soybean Specialist

Persistent wet weather is likely to push soybean planting into late May-early June in many areas of the state. Late planting reduces the cultural practice options for row spacing, seeding rate, and relative maturity.

Row spacing. The row spacing for June planting should be 7.5 to 15-inches, if possible. Row width should be narrow enough for the soybean canopy to completely cover the interrow space by the time the soybeans begin to flower. The later in the growing season soybeans are planted, the greater the yield increase due to narrow rows. Continue reading