GENERAL SITUATION

Hot and Dry! Cooler temperatures and rain showers have abandoned us. Cotton ranges from matchhead square stage in replanted cotton to cut-out in the earlier planted fields with little rain and not enough irrigation water. Most irrigated fields still look pretty good but more will start declining without additional rainfall.

Insect activity is generally light but we are seeing some increase in bollworm egg-lay again.

SCOUT SAFETY

Please contact your scouts or me if you are spraying the field they are scouting with an insecticide. We do not want anyone to be exposed unnecessarily to pesticides.

SCOUTING PROGRAM

The scouts are now checking primarily for bollworm eggs, worms, and beneficial insects in blooming cotton. They are still checking for fleahoppers and square set in a few fields that haven't begun to bloom. They have also begun checking for weevil punctures and pink bollworm infestation in the blooming cotton. I think overall the scouts are doing a good job. If you think so give them a word of encouragement when you see them.

BOLLWORM

Eggs ranged from 0-12,000 per acre or 0-31 per 100 plants.
Small worms have ranged from 0-5600 per acre or 0-17 per 100 plants.

Medium worms ranged from 0-6000 worms per acre.

Large worms ranged from 0-4000 worms per acre.

Worm activity is a combination of a few larger worms resulting from the heavier activity of the past 2 weeks, but we are seeing some fresh egg-lay in several fields. The sure way to not miss an increase in activity is to continue checking all fields you are concerned about.

Control of worms last week was acceptable in most fields. Some fields of larger cotton that were in the 2nd week of bloom had unacceptable control with Tracer®. The quantity of water used was lower and probably resulted in less than adequate coverage. I would try to use at least 10 gals./acre by ground and 5 gal./acre by air.

Bt COTTON

There have been some reports of worms surviving and damaging Bollgard® cotton. In all of the Bt cotton I have looked at you will see some damage to the terminals, small squares and some in the small bolls under bloom tags but the worm can't be found and the damage is minimal compared to the non-Bt fields. The worms must ingest some plant material before they will die.

COTTON FERTILITY

Cotton fertility programs should start with a soil test to determine what primary or micro nutrients are deficient. Fertilizers can be applied several ways to take care of these deficiencies and should be if they are cost effective. The primary deficiency we see in most area cotton is water and all the fertility or soil and plant amendments applied will not substitute for this primary ingredient.

Before you spend a lot of money on some of these products make sure they will be cost effective and increase your returns.

WEATHER DATA

Weather data for the past two weeks is included in the table that follows:

HEAT UNITS averaged 24 per day the past week. Heat units since 5-1 and 5-15 and 6-1 are compared with last year and a five year average in the table below.

DALLAS -- The same summer rains that have brought lushness to lawns have also given white grubs a place to thrive. To avoid a long and difficult battle with white grubs, Texas A&M University entomologists say now is the time to treat.

"The best time to treat with most products is in July," said Mike Merchant, urban entomologist with Texas Cooperative Extension at Texas A&M Dallas. "Really, the sooner you get the treatment on, the better off you'll be."

Traditionally, the best time to treat in North Texas is late July through early August , but Texas A&M entomologists say new chemicals on the market last a lot longer, and can be put out anytime in July to control grubs.

"For July applications, the best insecticides are imidacloprid (Bayer Advanced Lawn Season-Long Grub Control or Merit) or halofenozide (Ortho Grub-B-Gone, Mach 2)," said Merchant. "Halofenozide must be applied before the white grub reaches its final life stage. This is because this product affects the molting process. In its last growth stage a white grub will be unaffected by halofenozide. Applications made after Aug. 1 should be imidacloprid or diazinon only."

"Diazinon, which has been a wastewater contaminant problem for some communities, is shorter-lived than imidacloprid or halofenozide; therefore, the timing of application is more critical," said Merchant. "Diazinon will not be available after this year."

Another popular insecticide, Dursban, is no longer available for grub control.

"Many lawns will remain relatively free of white grubs and will not require treatments to control them," said Robert Crocker, research entomologist with Texas Agricultural Experiment Station at Texas A&M Dallas.

White grub damage can be detected by the presence of irregular-shaped areas of weakened or dying grass in the lawn.

"For the most part you go on past experience," Merchant said. "If you found grubs in your lawn last year, then it might be a good idea to go ahead and treat this year. You can also check for grubs by digging small holes, three to four inches deep, in several parts of your yard. Yards with four to10 grubs or more per square foot need chemical treatment."

"The size of this year's flight has been relatively modest," said Crocker. "However, this year we expect moderate to high populations of white grubs in some Metroplex lawns."

Four to six weeks after the major mating flight is generally the best time to treat. Gardeners who wait too long to treat can risk battling the older, more pesticide-tolerant grubs. Certain insecticides can be highly toxic to birds and other wildlife.

"Always read and follow label directions, and irrigate treatments promptly to water in the treatment," said Merchant. "Even though the ground may be moist from rain, you still need to irrigate to wash the insecticide into the root zone where grubs feed."

A fact sheet on white grub control in turfgrass is available through the Web at http://entowww.tamu.edu/extension/lawn.html or through a county Extension office.

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Educational programs conducted by the Texas Agricultural Extension Service serve people of all ages regardless of socioeconomic level, race, color, sex, religion, handicap or national origin. The information given herein is for educational purposes only. References to commercial products or trade names is made with the understanding that no discrimination is intended and no endorsement by the Cooperative Extension Service is implied.

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