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• Alabama Extension entomologist Ron Smith devoted part of the morning at the Wiregrass Cotton Expo, in Dothan, Ala., to underscore to southeast Alabama cotton producers why a little extra mindfulness with their insect management strategies can help them tighten their grips on major cotton insects.
Pyrethroids are effective, although they also adversely affect beneficial spider mites. Diamond has showed to be effective on the bugs during their post-bloom immature stage, especially when it is tank-mixed with one of the previously mentioned products.
On the other hand, single applications of Intruder, Carbine, imidaclorprid (AdmirePro), Belay and Vydate have been shown to be less effective than the others.
During July, as plant bugs linger and aphid populations build, Smith recommends using products effective against both species.
Intruder, Carbine, imadacloprid and Centric are most effective, while Diamond can be used with any of these, Smith says.
Mid-season over-sprays are especially important in cases where growers have invested in insect technology, especially now that some worm escapes have been detected.
“The over-spray is somewhat more important with Widestrike varieties, because they’re less effective on corn earworm species but, on the other hand, are more effective on armyworm species.”
He says that timing of this spray is best tailored to mid-July or early August depending on the grower’s location in the state.
Pyrethroids have proven to be an excellent fit during this period, he says.
Likewise, bifenthrin or Bidrin XPII have proven effective in cases where brown stink bugs are detected. Another option is to use the highest labeled rate of other pyrethroids.
A strange paradox within the past couple of years has been the heavy presence of armyworms in Alabama, although few have turned up in cotton.
“In both 2010 and 2011, we’ve had widespread outbreaks of what we call grass or rice strain of fall armyworms, although this strain primarily attacks pastures, hay and peanuts,” Smith says.
Fortunately for these growers, this strain is easy to control with insecticides, including pyrethroids.
The most damaging cotton pests in the South remains stink bugs. Smith does not foresee that changing anytime soon.
Eliminating the bugs may require as many as four sprays a year, at a cost of between $6 and $9 an acre.
Scouting is a critical safeguard against these bugs. The most effective way to scout for stink bugs is to examine 10- to 12-day-old bolls for signs of internal injury.
A laminated card has been developed to better ensure growers inspect the right-sized boll.
The kudzu bug, while not threatening to cotton, has emerged as a serious soybean pest and already is well entrenched in neighboring Georgia. Another species new to the region, the red-banded stink bug, is also primarily a soybean pest.
One especially serious threat is the brown marmorated stink bug, which is moving from Pennsylvania into the Appalachian region and is threatening the fruit- and apple-growing regions of the Carolinas, he says.
“Once we get it here, it may prove to be a terrible pest, especially on cotton, corn and pecans,” Smith says.
(Trade and brand names are for information purposes only. No guarantee, endorsement, or discrimination among comparable products is intended or implied by the Alabama Cooperative Extension System.)