May 18, 2012Chowan County Center
730 N. Granville Street
Edenton, NC 27932
(252) 482-6585
TO: Chowan County Farmers and Agribusinesses
FROM: Tim Smith
County Extension Director
SUBJECT: Thrips
Soybean Population
Wheat Yield Contest
Northeast Ag Expo Field Tour- July 26
Thrips:
Early thrips damage to both cotton and peanuts can result in significant yield losses for both crops. As a general rule, cotton seed treatments should provide 2-3 weeks of insect control at best. Planting conditions were ideal during early May and cotton planted then emerged quickly and got off to a great start. The recent cooler, wet, and cloudy weather has slowed things down a good deal since then. Several cotton acres will be entering the first true-leaf stage now or within the next week, which will likely coincide with the seed-treatment ending its period of protection. Thrips are hard to see in the field without magnification, but crinkled, gnarled, or possum-eared new growth is usually an indication of thrips feeding. Areas adjacent to wheat fields and other drying down vegetation are especially vulnerable. The treatment threshold for thrips in cotyledon stage cotton is 1 thrip per plant. For larger cotton, the threshold is 1 thrip per true leaf, meaning spraying is needed if you have 2-leaf cotton and find an average of two thrips per plant. Cotton is considered thrip-free after it reaches the 5 true-leaf stage. Keep in mind that sprays to control thrips can often increase aphid and spider mite levels.
For peanuts, at planting applications of systemic insecticides like Thimet or Acephate will generally provide a longer period of insect control than found with seed treatments alone. Even with an at-plant insecticidal application, thrips problems in peanuts can still occur and can cause major yield losses if left uncontrolled. The treatment threshold for thrips in peanuts is 25% leaf damage. As in cotton, foliar insecticidal sprays in peanuts can cause aphid and spider mite outbreaks, so make sure to check your fields before deciding to spray.
Soybean Planting
See the attached chart from Jim Dunpy and Jan Spears for soybean population recommendations. The chart is for determinate varieties (maturity group V and later) and it recommends increasing the populations by 20% if you are planting group IV and earlier.
Wheat Yield Contest
If you would like to enter the state wheat yield contest, give me a call at 482-6585 before you harvest to have your field measured and yield verified. We will need 3 acres to enter the contest.
Northeast Ag Expo Field Tour
This year the Expo field tour will be held the morning of July 26 in Pasquotank County at the farm of Charles Gray and Sons. The tour will focus on various aspects of corn production. There will also be a sorghum variety trial at the site. Pesticide recertification and certified crop advisor credit will be offered for attending this field tour.