Insect Update for the Week of July 7

A combination of adult tarnished plant bugs and clumping aphids are being reported from more fields and areas around the state each day. Overall, little rainfall has fallen in about two weeks. Therefore, crops, especially corn and cotton, are under some level of stress. Therefore, most growers are choosing to target both plant bugs and aphids with this application.

I have not had any calls on mites in the past few days but that does not mean that populations are not building in select fields. So far, abamectin at 10 oz. per acre has given good control on mites in treated fields.

Immature plant bugs are present now in the oldest cotton. I have observed several fields where a threshold of three immatures per 5 feet has been recorded on a black drop cloth. When plant bugs become imbedded in cotton in July (all stages present – eggs, immatures and adults) quite often multiple applications are needed to bring the population under control. For those that want to use the IGR Diamond, now is the time to do so. An adulticide plus Diamond, at 6-9 oz. per acre, should give control of the population for 14 plus days. It is my opinion that most of the adult plant bugs have now left wild host plants and are now in cotton. We just don’t seem to get that many moving from corn here in Alabama.

Moth traps in central Alabama captured an abundant number of both bollworm and budworm moths last week. 2014 may be the year that fieldmen, consultants, and scouts really prove their worth. There is just no way to time the appropriate chemistry at the proper time without someone monitoring insects. This looks like an above average insect year for cotton and we haven’t even reached the primary stink bug window yet. In sweeping for adult plant bugs last week, I was capturing brown stink bugs in about every set of sweeps.

How to Control Spider Mite and Plant Bug Infestations

Additional reports of economic spider mite infestations continue to come in, particularly from central and south Alabama. The heaviest infestations are already causing significant leaf shed in early square cotton. Fieldmen have reported that the lower leaves that show the greatest damage do not always have high mite numbers. Mites will continue to move up the plant to fresher leaves as the older leaves get ready to drop. Fieldmen should look a couple of nodes above the most damaged leaves in order to get a good handle on the number of mites present.

Several materials are recommended for mite control. However, some of these materials only seem to work in some locations. Examples are: bifenthrin, chlorpyriphos, dimethoate and propargite. One product in our 2014 recommendations is no longer on the market – dicofol. That leaves the newer mite chemistry as our best choice for control. These are abamectin (Agri-Mek), extoxazole (Zeal), fenpyroximate (Portal), and spiromesifen (Oberon). Abamectin is the most economical and has been the most widely selected for mite control. Ag suppliers are encouraged to have some on inventory since spider mites appear to be a growing problem.

Plant bugs continue to be reported in cotton that is squaring or approaching bloom. Plant bug immatures are now present in some of our oldest cotton. This indicates that adults deposited eggs a couple of weeks ago. Plant bug eggs are deposited into the stems of the plant in the more rapid growing areas. Therefore TPB eggs are not visible to fieldmen.

Adult plant bugs feed on tiny pin head squares in pre bloom cotton. Therefore pin head square retention is a good survey technique. Adult TPB’s can best be quantified with a sweep net. Once cotton begins to bloom, plant bugs seem to prefer feeding down in the canopy on the older squares. This results in “dirty blooms”. At this point (blooming cotton) a pin head square retention count is not the most reliable survey technique. It is also at this time that we begin to focus on the immature plant bugs instead of just the adults. The best tool for measuring immatures is the drop cloth. Therefore, in normal maturity cotton, we switch from a sweep net to a drop cloth about July 1-10 each season. Early instar nymphs are very small with long antennae and pale green in color. They move about more rapidly on a drop cloth than other insect species that may appear on the drop cloth in July.

The next few weeks should be focused on adult and immature plant bug numbers by fieldmen. While doing plant bug counts, aphids and spider mites can be observed. After July, or about the 3^rd or 4^th week of bloom, our primary focus should be on stink bugs. This would be true for the lower southeastern area of the cotton belt.

Cotton Insect and Pest Contols

We were cruising along last week with cotton insects kinda quiet. Thrips control was winding down on our latest planted cotton. The most prevalent observation was the white margined borrower bug, which could be found in most all fields. They were on cotton with 3 or 4 true leaves up to cotton knee high and squaring.

This week things have changed dramatically. Not to say every field has insect problems. However, in some fields, consultants are finding some level of plant bugs, spider mites, aphids and a few stink bugs. Generally, the older the cotton, the greater the chance some combination of these pests are present.

Let’s take these pests one at a time. Some have observed adult plant bugs feeding in terminals of pre-square cotton. Others report that plant bugs have dropped square retention to below 80% in cotton that will bloom within 7-10 days. A few stink bugs can already be found in these older fields. As we know from previous experience, stink bugs will attack bolls just after the dried bloom drops off if there are no larger bolls to feed on.

Added to these bug problems are the presence of aphids and spider mites. Aphids can be found clustering in the terminals of some plants in fields of older cotton. This is typically the way an economic aphid infestation usually begins. Spider mites have been treated in some fields already. Good results were obtained with Abamectin at 10 oz. per acre. Mites are still on borders of other fields and do not appear to be spreading yet.

With the combinations of pests present, it is difficult to control multiple species without a tank mix combination. My advice to growers, agrifieldmen and consultants would be to narrow your pest spectrum to the two species that offer the most near term damage potential and select a chemical or combination that will control those. It is just too early for me to consider three way tank mix combinations. At this time I believe it would be wise to target plant bugs (and stink bugs) first and I would place aphids second. These species can be controlled with a tank mix of two materials that would be rather inexpensive. A product that will give good control of plant bugs and stink bugs would be my first choice in the tank. If this product does not control aphids, I would add one that did.

This would leave the mite issue unaddressed. I just feel that we need to protect fruit first and deal with stress from spider mites in the weeks ahead.

There are a number of ways to tackle this tank mix issue for bugs and sucking pests. One would be a mix of pyrethroid and imidacloprid. There are too many to mention all at this time. I will be happy to discuss the various options by phone at 334-332-9501 if you are having problems deciding what approach to take.

Good luck and I’ll be back as we observe or hear of other information to pass along.

Updates from June 20, 2014

• Several more reports from diverse areas of the state about adult plant bugs at damaging levels in pin head square and older cotton.
• Plant bugs continue to increase on wild host plants on roadsides and field borders. Both dark (old) adults and immatures present in SE AL.
• Tobacco Budworms foliage feeding on peanuts near Enterprise, AL. Newer chemistry (Belt, Blackhawk, Steward) will be necessary for control.
• Fall armyworm (likely grass strain) feeding on peanuts in southwest AL. Pyrethroids will give excellent control.
• Snails in abundant numbers observed on cotton from Walnut Hill, FL to Columbus, MS. No controls suggested but net sampling for plant bugs difficult.

White Margined Borrower Bugs in Alabama

1. Ron Smith ‏@Ron_Smith23  6m

   AL growers are still battling thrips on late planted cotton and peanuts. @on_agfax

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2. Ron Smith ‏@Ron_Smith23  6m

   Immature WMBB have a red abdomen while the adults are black and about the size of adult plant bugs. @on_agfax

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3. Ron Smith ‏@Ron_Smith23  7m

   Control of WMBB can be achieved with Bidrin. Pyrethroids give good suppression. @on_agfax

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4. Ron Smith ‏@Ron_Smith23  7m

   WMBB usually associated with seeding crops growing under dry or droughty conditions. @on_agfax

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5. Ron Smith ‏@Ron_Smith23  8m

   White margined burrower bugs (WMBB) are appearing at damaging levels on several row crops in AL. @on_agfax

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Twitter Updates

Blog followers:

Following is a list of the information I have released this year (between mid January and late May) on Twitter. You can follow me on Twitter @Ron_Smith23 or look on the side bar of this blog to stay updated with my tweets year round.

1/15/14:

1. Ron Smith ‏@Ron_Smith23  Jan 15

   The loss of methyl parathion registration may be felt early if corn population of #stinkbugs is primarily brown species. @AlabamaCrops

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2. Ron Smith ‏@Ron_Smith23  Jan 15

   First field crop generation of #stinkbugs in 2014 usually occurs in corn and may be mostly brown species. @AlabamaCrops

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3. Ron Smith ‏@Ron_Smith23  Jan 15

   Early season 2014 #stinkbug populations are likely to be predominately the brown species, which are more cold hardy @AlabamaCrops

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4. Ron Smith ‏@Ron_Smith23  Jan 15

   Insect species that may have been impacted by low temps were #kudzubugs and southern green #stinkbugs @AlabamaCrops

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5. Ron Smith ‏@Ron_Smith23  Jan 15

   Early January temps reached single digits in North AL and were as low as 14 degrees along the Gulf Coast.

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6. Ron Smith ‏@Ron_Smith23  Jan 15

   The recent (Jan 6-8) low temps in AL likely caused mortality to some overwintering insect species.

2/26/14:

1. Ron Smith ‏@Ron_Smith23  Feb 26

   Thrips control in cotton is more important now in order to reach 3-5 bale yield potential of newer varieties. @AlabamaCrops

4/15/14:

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   Ron Smith ‏@Ron_Smith23  Apr 15

   Thrips to be collected this spring, prior to and after exposure to cotton seed treatments, for resistance monitoring by @SyngentaUS.

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2. Ron Smith ‏@Ron_Smith23  Apr 15

   Kudzu bugs active in Auburn, AL on April 12, a warm sunny day. @AlabamaCrops

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3. Ron Smith ‏@Ron_Smith23  Apr 15

   Abundant moisture in April could influence similar delayed thrips movement into cotton from wild hosts, as in 2013. @AlabamaCrops

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4. Ron Smith ‏@Ron_Smith23  Apr 15

   Significant cotton planting will begin next week (April 21-26) in central Alabama, assuming dry conditions. @AlabamaCrops

4/28/14:

1. Ron Smith ‏@Ron_Smith23  Apr 28

   To register for "Pest Patrol" updates, go to http://www.syngentapestpatrol.com  and follow directions.

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2. Ron Smith ‏@Ron_Smith23  Apr 28

   Insect conditions "Pest Patrol" program to be available again in 2014, sponsored by @SyngentaUS

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3. Ron Smith ‏@Ron_Smith23  Apr 28

   Grower concerns increasing about delayed cotton planting due to excessive moisture and frequent weather events.

5/1/14:

1. Ron Smith ‏@Ron_Smith23  May 1

   Both brown and southern green SBs found in wheat in several locations in central AL. Cold winter temps didn't suppress or kill as suspected.

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2. Ron Smith ‏@Ron_Smith23  May 1

   Early stage adult tarnished plant bugs found on wild host plants in central Alabama. Late planted cotton more susceptible to TPB injury.

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3. Ron Smith ‏@Ron_Smith23  May 1

   Thrips numbers remain low on wild host plants in central Alabama. Expect late movement to cotton as in 2013.

5/15/14:

1. Ron Smith ‏@Ron_Smith23  May 15

   Most of AL received from 1-5 inches of rain on May 14. Planting on hold until at least Monday, May 19.

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2. Ron Smith ‏@Ron_Smith23  May 15

   Two true leaf cotton at Prattvillle AL had 1-2 thrips per plant on May 13, regardless of treatment. Little damage evident.

5/28/14:

1. Ron Smith ‏@Ron_Smith23  2h

   Spidermites reported on 5/27 on cotton in the Eufaula area of SE AL.

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2. Ron Smith ‏@Ron_Smith23  2h

   Reports of spidermites on both seedling cotton and soybeans in Tenn. Valley area of Alabama, consultants concerned.

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3. Ron Smith ‏@Ron_Smith23  2h

   How long do acephate, dimethoate and Radiant need to be on plant for good thrips control? Four hrs b4 washoff showed little effectiveness.

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4. Ron Smith ‏@Ron_Smith23  2h

   Significant increase in thrips numbers during week of May 19-23 in central AL. 50% are now immatures, which indicates in-field reproduction.