Drought Causing Severe Threat From Twospotted Spider Mite

Two-spotted spider mites are infesting drought-stressed soybeans in Indiana. When left untreated, mites can cause severe and irreversible foliar damage to soybean plants.
Two-spotted spider mites are infesting drought-stressed soybeans in Indiana. When left untreated, mites can cause severe and irreversible foliar damage to soybean plants.

 

The severe and prolonged extreme heat and rainfall shortages that have led to moderate and severe drought conditions across Ohio have also led to reports of the twospotted spider mite, a dangerous pest that can cause severe damage to soybeans, including the death of the entire plant, an Ohio State University Extension entomologist said.

Many growers have already reported finding twospotted spider mites on soybeans, said Ron Hammond, who also has an appointment with the Ohio Agricultural Research and Development Center.

Spider mites, which feed on the underside of the foliage with sucking mouth parts and can be destructive when abundant, thrive on plants that are under stress, especially in hot, dry field conditions, he said.

This is significant, considering that all of Ohio except for small portions of some counties near the West Virginia border is experiencing moderate drought, with areas near the Indiana and Michigan borders experiencing severe drought as of July 24, according to the most recent U.S. Drought Monitor.

“Numerous areas in the drier areas of Ohio are already seeing them, and some fields are already being sprayed,” Hammond said. “Mites are showing up not only on field edges but also within the field.

“Twospotted spider mites have the potential to cause more yield loss than any other insect, with the damage caused by the mites being severe enough to kill the entire plant. Growers who have a bad infestation will not see any yield from the affected area.”

Typically, Ohio growers are impacted by twospotted spider mites in July or early August, because moisture levels earlier in the year are usually high enough to keep the pests at bay, Hammond said.

But the early hot, dry conditions and low soil moisture levels have caused the pests to appear earlier and, because many soybean plants are stressed, the pests have more potential to impact entire fields instead of just the edges, Hammond said.

“If we were having normal rainfall, we wouldn’t be worried about mites right now,” he said. “In some parts of the state, soils are very dry and crops are starting to suffer.”

Currently, topsoil moisture was rated 53% very short, 37% short and 10% adequate, with no surplus, according to the latest U.S. Department of Agriculture Weekly Crop Report.

Hammond said growers should begin scouting their fields for twospotted spider mites now. Spider mite infestations can first be noticed by yellow stippling on the upper surface of the leaves, he said. The mites themselves, which are found on the underside of the leaves, can be identified using a good hand lens.

“In making an assessment of a spider mite-infested field, it is important that one recognize the early sign of mite feeding, which is the stippling or speckled effect that initially appears on the foliage when foliage is still green,” he said.

Growers can use the following criteria to determine whether to spray for twospotted spider mites:

  • If mites are barely detected on the underside of leaves in dry locations or on the edges of a field and injury is barely detected, this is a non-economic population and growers should do nothing.
  • If mites are easily detected on the underside of leaves along the edges of fields or perhaps on leaves in dry areas throughout a field and most foliage are still green, but yellow stippling caused by mite feeding is becoming detectable on upper side of leaves with the underside showing mite feeding, this is still non-economic but warrants close monitoring.
  • If growers find that many of their plants are infested, with plants showing signs of stippling such as speckling and discoloration of some of the leaves on the field edges or throughout the field, they should consider spraying the entire field if mites are common throughout the field.
  • If growers find that all plants in the area, whether along field edges or within the field, are heavily infested and are discolored with wilted leaves, severe injury is occurring and a rescue treatment will save the field.
  • If growers find extremely high twospotted spider mite densities, with much of the field discolored, stunted, and with many plants dying down or already dead, a rescue treatment will be beneficial only if new growth occurs following late summer rain.

“While growers often wonder if it is worth the costs to spray during a drought, past experience shows that when soybeans are protected from mites, later rains in August will allow the soybeans to recover somewhat and give acceptable yields compared to fields where mites were not controlled,” Hammond said.

But, he cautioned, if the drought and extreme heat continue, none of these options will provide long-term control.

“Fields may need a second treatment later, so it’s important that growers continue to scout their fields,” Hammond said. “And if a second treatment is required, growers should use a different material to help reduce the chances of miticide resistance from developing in the mite.”

Growers can find more information on when they should spray for twospotted spider mites and other treatment guidelines here.

“The earlier you recognize mite infestations, the quicker you can deal with them prior to economic losses,” he said.

Topics:

Leave a Reply

Insecticides Stories

InsecticidesSyngenta Recommends Soybean Scouting To Prevent Economic Loss From Insects
July 22, 2015
Proper soybean insect pest control begins with scouting. As the warm weather continues, Syngenta encourages growers to implement a scouting Read More
InsecticidesVestaron Biopesticide Approved In California
June 29, 2015
Vestaron Corporation, a developer of insect control products derived from naturally occurring peptides, today announced that its VST-006330-EP biopesticide has received Read More
InsecticidesValent’s Zeal SC Miticide Receives EPA Approval
June 29, 2015
Valent U.S.A. Corporation announced today that Zeal SC Miticide has been registered by EPA with a new liquid formulation that Read More
Tim Hassinger Dow AgroSciences President and CEO
Crop InputsDow Details Molecular Forensic Technology For Insecticides
June 10, 2015
Just like each human fingerprint is unique; microbes that have been developed to produce naturally based crop protection products are Read More
Top 100 Articles
Crop InputsLand ‘O Lakes, United Suppliers Finalize Merger
August 24, 2015
According to a press release on August 24, owners of United Suppliers, Inc. and members of Land O’Lakes, Inc. “have Read More
West Central Cooperative, Jefferson, IA
CropLife 100Iowa Cooperatives To Explore Unification
August 19, 2015
The boards of directors at two of Iowa’s leading farmer-owned cooperatives yesterday signed a letter of intent to study the Read More
CropLife 100Southern States Coop Hosting Drone Flight This Friday
August 3, 2015
Southern States Cooperative — No. 9 on the CropLife 100 — is hosting an FAA-approved drone demonstration at Grandview Farms Read More
CropLife 100Aligned Ag Distributors Adds Four New Owners
July 30, 2015
Aligned Ag Distributors LLC has announced the addition of four new customer/owners to Franklin Holding Co. LLC. They are: The Read More
CropLife 100Pinnacle Purchases California-Based Specialty Crops Retailer
July 20, 2015
Pinnacle Agriculture Holdings has successfully acquired California-based NH3 Service Co.  Operating as part of Pinnacle’s Performance Agriculture brand, the new locations Read More
Asmus Farm Supply liquid fertilizer facility features 20,000 square feet
CropLife 100Slideshow: Asmus Farm Supply Shows Off Its New Liquid Fertilizer Facility
July 15, 2015
Asmus Farm Supply, Rake, IA, recently added a new liquid fertilizer facility to its company operations. The new liquid fertilizer Read More
Latest News
StewardshipBee Buffer Strip Initiative Seeks 100 Ohio Farmers
August 31, 2015
The U.S. Bee Buffer Project, an initiative of the Pollinator Partnership (P2), Burt’s Bees and The Burt’s Bees Greater Good Read More
2015 ShowStopper Award, MAGIE
EquipmentA ShowStopper From Case IH: The Patriot 2250
August 31, 2015
For nine years now, visitors to the yearly Midwest AG Industries Exposition (MAGIE) show have been tasked with not only Read More
Crop InputsMonsanto, FMC Expand Roundup Ready PLUS Platform
August 31, 2015
FMC Corp. and Monsanto Co. announced today an expanded agreement to continue their participation in the Roundup Ready PLUS Crop Read More
Deere Nutrient Applicator
Eric SfiligojThe Good & Bad News From MAGIE
August 31, 2015
As I write this column, I’ve just returned from the annual Midwest AG Industries (MAGIE) trade show in Bloomington, IL. Read More
CPS Morenci receiving its 4R certification
StewardshipCPS Morenci Becomes First Michigan Facility Certified I…
August 31, 2015
The 4R Nutrient Stewardship Certification Program has announced that Crop Production Services, Inc.’s facility located in Morenci, MI, has been Read More
EquipmentDeere Announces Soucy Track Distribution Alliance
August 28, 2015
John Deere announces an alliance with Soucy Track to sell and distribute products through the John Deere dealer channel. “This Read More
FertilizerFall-Applied Phosphorus: A Rooted Investment
August 28, 2015
As commodity prices decrease and input prices continue to rise, farmers are seeking more efficient strategies for meeting a high Read More
Monsanto Sign
Crop InputsWhat’s Next For Monsanto, Syngenta?
August 28, 2015
After dropping its $47 billion bid to take over Swiss agribusiness firm Syngenta, Monsanto may be turning its focus to Read More
Golden Harvest Corn stalks
Crop InputsMonsanto: Syngenta Not The Only Horse In Crop Protectio…
August 28, 2015
Monsanto Co, having ditched an audacious $46 billion (£30 billion) offer for Syngenta AG, may downshift to a humbler strategy Read More
ManagementConsolidation hits and a miss; And a look at China’s ch…
August 28, 2015
As Monsanto suspends its pursuit of Syngenta, consolidation news at the retail and distribution level heats up. CropLife magazine’s Executive Read More
Corn Field
MicronutrientsHuma Gro Introduces New Boron Liquid Nutrient Formulati…
August 28, 2015
BORO-MAX, a new boron (B) 10% liquid nutrient formulation, has been added to the Huma Gro product line. This new Read More
Crop InputsNFU: Monsanto Decision To Withdraw Syngenta Bid ‘…
August 26, 2015
National Farmers Union (NFU) President Roger Johnson said the organization was very pleased by the news that Monsanto has withdrawn Read More
Crop InputsMonsanto Withdraws Bid For Syngenta
August 26, 2015
Monsanto Co. abandoned its latest effort to acquire Syngenta AG, the world’s top maker of pesticides, after a sweetened bid Read More
Syngenta Sign
Crop InputsSyngenta Comments On Monsanto Announcement
August 26, 2015
The Board of Syngenta confirms that it received a verbal proposal from Monsanto to acquire the company at a price Read More
Case IH Patriot 2250 Sprayer
EquipmentHigh-powered Case IH Patriot 2250 Sprayer Pushes Throug…
August 26, 2015
Engineered with more muscle, the new 660-gallon-capacity Patriot 2250 sprayer features best-in-class horsepower, along with the fuel efficiency that comes Read More
Crop InputsLand ‘O Lakes, United Suppliers Finalize Merger
August 24, 2015
According to a press release on August 24, owners of United Suppliers, Inc. and members of Land O’Lakes, Inc. “have Read More
TMX-2050 In-Cab Display Launch Run Screen
Eric SfiligojPrecision Ag Could Shine In Increased Spotlight On Agri…
August 24, 2015
By any measure, 2015 is turning into one of the most challenging years agriculture has ever experienced. All throughout good Read More
ManagementCrop Conditions In Minnesota and Traveling Time
August 21, 2015
Editors Paul Schrimpf and Eric Sfiilgoj discuss the crop outlook from a field trip to Minnesota and upcoming travel plans. Read More