Tuesday, June 22, 2010

Spider mites, tarnished plant bugs, tobacco budworms, stink bugs, and yellow striped armyworms observed

Cotton 6/21/2010 - Spider mites were reported infesting select fields in Talladega county today. This is the second call I have had concerning mites on cotton in the past week. This problem could spread in coming weeks with the hot weather. Thunderstorms rumbled through parts of the state on Saturday. But, some areas remain dry with intense heat.

I have received no new reports of tarnished plant bug (TPB) activity. Hopefully, this heavy migration from wild hosts will be of short duration. Fields that were treated for TPBs in southwest Alabama are clean this week with high square retention. Unsprayed fields have some level of plant bugs left but they do not appear to be causing greater than 20% square loss.

Today, I collected early instar tobacco budworm larvae from tobacco at the Gulf Coast Research Center. Tobacco is being used as a sentinel crop at three sites to monitor budworm activity (Prattville, Fairhope, and Headland, AL). Based on observations, it appears that some level of budworm egg lay has been going on for two or more weeks. Growers with conventional cotton should be very selective in spraying for any other insect during this budworm flight. Keep beneficials in conventional cotton as long as possible. Hopefully, up to July 15 in central Alabama and July 20 in central Alabama.

One insect that may make it difficult to leave uncontrolled after the first week of bloom is the stink bug. Numerous brown stink bugs (BSB) can be found in many fields at present. They will not damage pre-bloom cotton but as soon as the bloom drops they will attack the thumb sized boll causing abortion from the plant. I am seeing a level of BSBs that will require controls in many fields by the second week of bloom. It does not appear that these BSB are moving to corn or other hosts, but instead are just waiting for the first small bolls. In fact, when those in corn begin looking for a new home, we likely will have many move into cotton.

Yellow striped armyworms, in low numbers, were observed in numerous BGII fields in Monroe county today.

On other crops - tobacco budworms, fall armyworms and yellow striped armyworms were reported feeding as foliage feeders on peanuts in Monroe county (southwest AL) today. Numbers were low (one per 4-5 row feet) in many fields but a few fields had numbers approaching concern and will be watched closely during the next 7-10 days. The average peanut field has about six inches of foliage at this time.