Tuesday, January 21, 2014
fall-armyworm-net-arkansas-08242012-feature

Texas: Many Insects Have Survival Strategies for Cold Weather

AgFax.Com - Your Online Ag News Source


Will the extremely cold weather Texas experienced recently have any effect on insect populations this spring?

Probably not, said Erfan Vafaie, Texas A&M AgriLife Extension Service integrated pest management specialist at Overton.

“It depends upon the insect,” said Vafaie.

Red imported fire ants, for example, burrow down so deeply in the soil that they’re unlikely to be affected by cold weather, Vafaie said.

 

“They tend to be quite ‘insulated’, if you will, from the extreme temperature changes — unless there’s a very long sustained cold, which may slowly make its way down into the depths,” he said.

It’s been suggested by other entomologists, Vafaie said, that a colder winter may reduce the populations of mosquito species that carry West Nile virus during the following summer.

“However, we don’t know for a certainty, and since this winter has been quite a unique one in Texas, we’ll have to wait and see how insect populations have been affected.”

What is known is that insects generally have several biological mechanisms for dealing with cold weather, even extremely frigid weather like large parts of Texas had in late December. Vafaie’s previous work under the supervision of Dr. Brent Sinclair, a prominent insect low-temperature biologist in Ontario, Canada, gave him a strong foundation and knowledge on insect cold tolerance, he said.

“There are many places that often experience much cooler climates than Texas, such as Toronto, that had below minus 20 this December,” Vafaie said. “Although it may seem as though our little insect friends would not be able to live at such low temperatures, many have adapted the ability to survive in such environments.”

Generally speaking, insects have three main strategies for dealing with the cold: freeze tolerance, freeze avoidance and migration, he said.

“Internal ice formation would kill most organisms, but some insects have specialized mechanisms to deal with ice,” Vafaie said. “Some insects, such as the woolly bear, a moth larva, and goldenrod gall fly larvae, can tolerate freezing by the use of specialized proteins.”

He noted that though such insects are termed “freeze tolerant,” if they are taken from the field during the summer and placed in a freezer, they aren’t likely to survive.

“Typically, certain environmental cues are involved. For example, shorter days and cooling temperatures may induce mechanisms that help the insect tolerate freezing,” Vafaie said. “When the weather warms back up, they thaw and become active again.”

Other insects cannot tolerate freezing, but have other mechanisms to prevent ice formation in their cells, he said.

“We call 32 Fahrenheit the freezing point of water, but the temperature at which ice forms depends on the content of the solution,” Vafaie said. “For example, saltwater at a concentration of 23.3 percent may not freeze until the temperature is minus 6 degrees Fahrenheit. In the same way, some insects use certain compounds called ‘cryoprotectants,’ similar to the ethylene glycol found in your car’s antifreeze, that lower the temperature at which freezing occurs. This helps them survive at subfreezing temperatures.”

The third strategy, migration, is also commonly used by some species of insects. In East Texas, one of the most common examples of this strategy is the fall armyworm, he said.

The fall armyworm is actually the larval form of a migrating moth, he said.

Fall armyworm moths migrate in the millions northward from South Texas in the spring and summer. Upon arrival, each moth will deposit a clump of 50 or more eggs on individual blades of grass. When the eggs hatch, the larva quickly go on maneuvers en masse for food. They will move across pastures, devouring wide swathes of grass in their wake, like an advancing army, hence their name.

Another migratory example is the monarch butterfly, Vafaie said.

“Monarchs migrate to Mexico and Southern California every winter,” he said.

One thing that may defeat many of these survival strategies, however, is when there are multiple incidences of very cold weather with warm temperatures in between. Such rollercoaster weather can decrease insect survival or reproductive potential, according to Vafaie.

“It’s not that they don’t have strategies adapted to deal with frequent temperature variations; it just comes at a cost, for example survival or reproduction,” he said.

But even when winter knocks back survival numbers, nature has a way of adjusting, Vafaie said.

“Due to the relatively short generation time of some of our biggest pests, like aphids, whiteflies and mites, their populations can grow exponentially even if winter survival is low.”

Tags: , , , , , , , ,


Leave a Reply

Name and Email Address are required fields. Your email will not be published or shared with third parties.

Sunbelt Ag News

    Rice Commentary: The Case for Neonicotinoid Seed Treatments11-22

    U.S. Rice: Rain Stalls Texas 2nd Crop Harvest; Crop Sales Continue11-22

    Rice Market: Sale to Iraq Moves the Market11-22

    AgFax Grain Review: Syngenta Lawsuits Pile Up; GMO Seed Companies Sue Hawaii11-21

    Rose on Cotton: Looking for the Positives This Week11-21

    Grain Drying: What Happens After Sudden Temperature Drop?11-21

    Is Your Lifestyle Costing You the Farm?11-21

    Grain TV: Lower Barge Rates Boost Basis Levels11-21

    DTN Livestock Close: Cattle Futures Solidly Higher11-21

    Farmers Storing Grain Need to Weigh Risk Management Factors – DTN11-21

    Peanut Harvest Updates From Southeast, Delta And Southwest – AgFax11-21

    Cleveland on Cotton: 57 Cents – ‘The Bottom is In’11-21

    Ag Labor: Immigration Order Provides Little Long-Term Benefit – DTN11-21

    Doane Cotton Close: Decline in Chinese Production Offers Support11-21

    AFB Grain-Soybean Close: Strong Soybean Gains, Little Movement in Corn, Wheat11-21

    Southern Soybean, Corn Harvest Reports, Round One – AgFax11-21

    AFB Cotton Close: Futures Rebound11-21

    AFB Rice Close: Prices See More Slight Gains11-21

    DTN Cotton Close: Settles Higher on Light Volume11-21

    DTN Grain Close: Soybeans Boosted by Demand11-21

    USDA: Peanut Price Highlights11-21

    Oklahoma Pecans: Deliveries Remain Light11-21

    Georgia Pecans: Buying Interest Very Active11-21

    Ag Policy: Farm Bills Need Long-Term View11-21

    Cotton Market Weekly Review by Region11-21

    DTN Livestock Midday: Cattle Futures Surge Higher11-21

    A Closer Look at Impacts of Olympic Averaging of Prices and Yields11-21

    Arkansas Cattle: Ranchers Should be Alert to Acorn Poisoning11-21

    DTN Grain Midday: All 3 Commodities Go Higher11-21

    Economist: Livestock Industry Will Have Strong Rebound11-21

    DTN Dried Distillers Grain: Cheaper Feed Source for Beef Producers?11-21

    Mississippi Outdoors: Common Deer Parasites Do Not Affect Venison11-21

    DTN Cotton Open: Trades Higher after No Notices Issued11-21

    AgFax Wildlife Review: New E-Book Offers Tips for Gardening in South11-21

    DTN Livestock Open: Cattle Futures to Start Mixed11-21

    Weather Challenges Florida and Iowa Farms — DTN11-21

    Vilsack: Immigration Order Creates ‘Stability’ in Ag Work Force — DTN11-21

    DTN Grain Open: Lower Start Across Board11-21

    Keith Good: What’s Next for Meat Labeling?; Sugar Prices Take Tumble11-21

    Texas Cotton Harvest – Still Some To Go – AgFax11-20

    Mississippi: Water Conservation Summit, Stoneville, Dec. 1011-20

    Farm Internet Service Still Slow or Non-Existent, But Improving – DTN11-20

    Yield: Important Factor in Your Irrevocable Farm Program Choice11-20

    U.S. Grain Transportation: Weekly Inspections Reach Record11-20

    U.S. Drought Outlook: Improvements Expected for California, Southwest11-20

    U.S. Energy: Planned Refinery Maintenance Light in 201411-20

    Propane Stocks: Post Slight Increase11-20

    Gasoline Prices: Decrease by 5 Cents11-20

    Diesel Prices: Average Drops 2 Cents11-20

    Livestock: Arctic Chill Catches Markets Flatfooted – DTN11-19

    Farm Runoff Targeted for Regulation Following Algal Bloom Shutdown – DTN11-19

    Soybeans: China May Import More Non-GMO Beans – DTN11-19

    Mississippi Outdoors: Free Apps Can Aid Deer Hunters11-19

    Big River Rice And Grain Enhances, Expands Facilities In Arkansas, Louisiana11-19

    Farm Bill Commodity Program: Decisions and More Decisions11-18

    Young Farmers: USDA is the ‘Lender of 1st Opportunity’ – DTN11-18

    Tax Extenders: Farm Groups Push Congress to Renew Section 179 This Year – DTN11-18

    AgFax Rice Review: Iraq Passes on U.S. Rice; Australia, China Sign FTA11-18

    USDA: Weekly National Peanut Prices11-18

    DTN Fertilizer Trends: Prices Show Little Movement11-18

    North Carolina: Bt Resistant Armyworms Migrating North11-18

    Georgia Cotton Commission Meeting, Production Workshop, Tifton, Jan. 2811-18

    Sunbelt Ag Events

     

    About Us

    AgFax.Com covers agricultural trends and production topics, with an emphasis on news about cotton, rice, peanuts, corn, soybeans, wheat and tree crops, including almonds, pecans, walnuts and pistachios.

      

    This site also serves as the on-line presence of electronic crop and pest reports published by AgFax Media LLC (formerly Looking South Communications).

        

    Click here to subscribe to our free reports.

      

    We provide early warnings and confirmations about pests, diseases and other factors that influence yield. Our goal is to quickly provide farmers and crop advisors with information needed to make better and more profitable decisions.

         

    Our free weekly crop and pest advisories include:

    • AgFax Midsouth Cotton, covering cotton production and news in Alabama, Arkansas, Louisiana, Mississippi, Tennessee and Missouri.

    • AgFax Southeast Cotton, covering cotton production and news in Alabama, Florida, Georgia, North Carolina, South Carolina and Virginia.

    • AgFax Southwest Cotton (new for 2013!), covering cotton production and news in Texas, Oklahoma, Kansas and New Mexico.

    • AgFax West (formerly MiteFax: SJV Cotton), covering California cotton, alfalfa, tomatoes and other non-permanent crops in California's Central Valley.

    • AgFax Rice covering rice production and news in Arkansas, Louisiana, Mississippi, Missouri and Texas.

    • AgFax Peanuts, covering peanut production in Alabama, Arkansas, Florida, Georgia, Louisiana, Mississippi, North Carolina, South Carolina, Texas and Virginia.

    • AgFax Southern Grain: covering soybeans, corn, milo and small grains in Southern states.

    • AgFax Almonds, covering almonds, pistachios, walnuts and other tree crops in California's Central Valley.

    • AgCom 101, providing guidance to ag professionals involved in social media.

    Our newsletters are sponsored by the following companies: FMC Corporation Chemtura Dow AgroSciences.

          

    Mission statement:

    Make it as easy as possible for our community of readers to find and/or receive needed information.

              

    Contact Information:

    AgFax Media. LLC

    142 Westlake Drive Brandon, MS 39047

    601-992-9488 Office 601-992-3503 Fax

    Owen Taylor Debra L. Ferguson Laurie Courtney

          

    Circulation Questions?

    Contact Laurie Courtney