Management practices still needed for effective TSWV control
It seems that no matter how many tools you have in your toolbox, you always need one more tool to get the job done right. The same is the case when managing tomato spotted wilt virus (TSWV) in peanuts. While many growers rely on the tool of resistant cultivars to control the disease, experts and growers agree it’s better to use more than one tool to help fix this problem.
It’s no secret TSWV has been known to devastate peanut fields. What is of equal concern is the control of thrips, the carrier of TSWV. While no singular practice completely manages thrips, there are four leading in-field practices that should be considered to manage the pest, which also can lead to a reduction in TSWV and minimizes the risk of loss to a grower’s peanut crop. Practices such as cultivar selection, planting time, closer rows and using THIMET® have been shown to help suppress TSWV.
“I think it would be very bad of us to assume we don’t have to worry about TSWV,” Mark Abney, peanut entomologist with the University of Georgia College of Agricultural and Environmental Sciences, explained. “What I fear is that we will back off from some of the cultural practices that we’ve been doing for years and set ourselves up for problems if the thrips ever overcome the resistance.”
While some of the management practices that help control thrips seem standard practice, it’s good to be reminded of their importance. Practices that help control thrips, and therefore help reduce TSWV, include planting resistant cultivars, later planting and twin rows. Another proven tool that provides control of thrips and a moderate level of TSWV suppression is using THIMET insecticide (active ingredient phorate) in-furrow.
Thrips overwinter in winter annual weeds surrounding fields. If a warm day pops up in April or early May, those weeds will begin to die and thrips will begin flying and looking for new hosts. Planting too early may create a new plant with lots of bare soil that becomes the target host for thrips. Abney explains that waiting to plant until May 10 generally allows time for thrips to take flight before the plants emerge.
“The last two years we’ve seen the peak thrips flight the last week of May; however, we don’t yet know if there’s a new pattern emerging,” Abney said. “Even if they do have a later flight, planting around May 10 and then allowing five to seven days for emergence, the thrips flight would have decreased some.”
Abney notes that increased seeding rates and planting in twin rows also are management techniques that help decrease thrips pressure.
“The canopy that is created by increased seeding rates and planting in twin rows provides a lot less contrast between green plant and the ground and is less appealing to thrips,” Abney stated.
Another method of controlling thrips and reducing the impact of TSWV is to use THIMET in-furrow. Regardless of weather or planting conditions, for years THIMET been proven to do something no other competitor can – consistently reduce the number of thrips on plants and provide a moderate level of suppression of TSWV.
Peanut grower Tim Burch of Newton, Georgia, has confidence in the protection THIMET delivers to his crop.
“When I’m choosing a product, I want to think that it’s going to give me the best return on my investment. THIMET has done that for me,” Burch commented.
In fact, THIMET has proven to give peanut growers the best return on their money. Studies taken during the 2013 and 2014 growing seasons show that THIMET improves peanut yields by nearly 400 pounds per acre.1
Burch is familiar with the convenience of seed treatments that are noted to control thrips; however, he prefers to use the in-furrow THIMET treatment.
“There hasn’t been a big increase in yield using the seed treatment, so I prefer to stay with THIMET for thrips control and higher yield,” Burch said.
As long as there are thrips, there will be a conversation about how to best manage these insects. A combination of cultivar selection and in-field management practices such as planting dates, twin-row planting and applying THIMET in-furrow will be the best tools to help manage thrips and TSWV.
To learn more about how THIMET can help you control thrips and reduce the risk of TSWV, contact your consultant or learn more at www.amvac-chemical.com.
1 Based on all available data points from Virginia Tech, NC State Univ., Clemson Univ., Univ. GA, and Auburn Univ. cooperators. All seed treated with fungicide.
AMVAC and THIMET are trademarks owned by AMVAC Chemical Corporation. Dynasty and CruiserMaxx are trademarks of Syngenta Participations AG.
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