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

Crop InputsBayer: 5 Reasons We Disagree With Maryland Neonic Ban
April 12, 2016
We’re disappointed that the Maryland legislature chose not to stand up for sound science and the rights of Maryland’s homeowners Read More
Corn Earworm
FungicidesInsects And Diseases In 2016: Early Planting, More Stress
April 4, 2016
First, the good news: If we consider all the issues growers and retailers are facing right now — low commodity Read More
Crop InputsBayer: The Science Is On Our Side In Belt Insecticide Battle
April 1, 2016
You may have seen some media stories about Bayer’s current disagreement with EPA over registrations for our pesticide flubendiamide, marketed Read More
InsecticidesEPA Moves To Cancel The Insecticide Flubendiamide
March 7, 2016
The U.S. EPA is issuing a notice of intent to cancel all Bayer CropScience, LP and Nichino America, Inc., flubendiamide Read More
Trending Articles
Eric SfiligojPity The Monsanto Haters
May 23, 2016
An old saying goes thus: “Be careful what you wish for. You just might get it.” Given current events, there Read More
Monsanto Luling Plant
Crop InputsReport: Bayer Eyeing Monsanto For Possible Mega-Merger
May 16, 2016
Bayer AG is exploring a potential bid for U.S. competitor Monsanto Co. in a deal that would create the world’s Read More
Aerial Drone
Precision AgA Deeper Dive Into The Future Of Precision Ag
May 9, 2016
For about two decades now, through the good and the bad times, the ups and the downs inherent in agriculture, Read More
Palmer amaranth in soybean stubble
HerbicidesWSSA: Billions In Potential Economic Losses From Uncontrolled Weeds
May 4, 2016
What losses would corn and soybean growers experience if they were forced to eliminate herbicides and other control techniques from Read More
Eric SfiligojReasons For Hope In Commodity Prices
May 2, 2016
For many months now, the doomsayers have ruled the day in agriculture. Too much supply with too little demand would Read More
Eric SfiligojMissing The Family Ties In Agriculture
April 25, 2016
By its nature, the agriculture market is cyclical. Up and down cycles come and go with a regular pattern. For Read More
Latest News
Crop InputsLand O’Lakes Announces Minnesota Water Quality Pa…
May 25, 2016
Governor Mark Dayton and Land O’Lakes, Inc. President and CEO Chris Policinski today announced a new public-private partnership to protect Read More
Soybean Plant closeup
Industry NewsMonsanto Rejects Bayer Bid; Open To More Talks
May 25, 2016
Monsanto Co, the world’s largest seed company, turned down Bayer AG’s $62 billion acquisition bid as “incomplete and financially inadequate” Read More
Corn close up
Crop InputsArysta LifeScience Establishes Global Headquarters In R…
May 25, 2016
Arysta LifeScience has announced plans to relocate its global headquarters from West Palm Beach, FL, to Cary, NC, over the Read More
fertilizer blending and storage, Top 100
BlendersCHS Dakota Expansion Features AGCO’s GSI InterSys…
May 25, 2016
The continued growth of precision agriculture has increased farmer use of customized fertilizer blends best-suited for their soil conditions. Several Read More
ManagementAgriculture 3.5: A Bumpy Road Ahead
May 24, 2016
You may have read my article a few years ago on Agriculture 3.0, which is a term I coined to Read More
Topcon’s X30 display with CropSpec sensors
EquipmentGPS Autosteer Systems: Product Updates From Precision A…
May 24, 2016
Throughout 2015 GPS Steering solutions continued to evolve from what was once an after-market add on, to today’s cab where Read More
Trimble TMX-2050 In-Cab Display
Eric SfiligojThe Precision Ag Revolution Continues
May 24, 2016
It’s funny how much “the first time” tends to mean to someone as they get older. I sometimes can’t recall Read More
Eric Wintemute, AMVAC
Precision AgAMVAC Ups The Ante With New Precision Ag Technology
May 24, 2016
A potentially industry-changing at-plant soil treatment system from American Vanguard Corp., or AMVAC, is coming soon to large growers in Read More
Dry and Liquid Plant
CropLife 100CropLife 100 Map
May 24, 2016
The new CropLife 100 map shows the locations of each of the headquarters of the 2015 CropLife 100 retailers. The interactive Read More
Southern States Cooperative
Corn Field
Industry NewsTiger-Sul Names Veteran Account Manager To Lead Central…
May 23, 2016
With the continuing growth of the sulphur bentonite and precision crop nutrient industry, global agriculture firm H.J. Baker has announced that Read More
Bayer sign
Industry NewsReuters: Bayer Defies Critics With $62 Billion Monsanto…
May 23, 2016
German drugs and crop chemicals group Bayer has offered to buy U.S. seeds company Monsanto for $62 billion in cash, Read More
Eric SfiligojPity The Monsanto Haters
May 23, 2016
An old saying goes thus: “Be careful what you wish for. You just might get it.” Given current events, there Read More
Industry NewsCompass Minerals Hires Industry Veteran To Lead Plant N…
May 19, 2016
Compass Minerals has hired plant nutrition industry veteran Vatren Jurin to steer the company’s portfolio expansion into specialty liquid micronutrient Read More
ASMARK Retailers LIVE! Tour 2016 Group shot The Andersons
CropLife 100The Andersons Rejects Unsolicited Proposal From HC2
May 19, 2016
The Andersons, Inc. has announced that its Board of Directors has rejected two non-binding, highly conditional, unsolicited proposals from HC2 Read More
glyphosate
Crop InputsWHO: Glyphosate ‘Unlikely’ To Cause Cancer
May 16, 2016
Via Reuters.com reporter Kate Kelland: The weed-killing pesticide glyphosate, made by Monsanto and widely used in agriculture and by gardeners, Read More
dicamba, Roundup Ready 2 Xtend
Crop InputsASA: No Dicamba On Roundup Ready 2 Xtend In 2016
May 16, 2016
While Roundup Ready 2 Xtend (RR2X) are tolerant to dicamba and glyphosate herbicides, no dicamba herbicides will be approved for Read More
CPP, glyphosate, dicamba, atrazine,
Crop InputsReport: Congress Pressing EPA On Glyphosate Review Hand…
May 16, 2016
Via Reuters.com reporter P.J. Huffstutter: U.S. lawmakers have asked EPA to explain why it published – and then withdrew – Read More