Texas Agricultural Extension Service

Volume XXVII No. 18 June 29, 2001 GENERAL SITUATION: Hot and dry for the week. Good cotton, corn and grain maturation weather. Grain harvesting was about half over, along with corn. Cotton defoliation will commence in some early planted fields in about a week or so. Boll weevils and whiteflies increased this week. Texas A&M Center Row Crops Field Day Friday, July 6, 2001 There will be a field day for all on Friday, July 6. Registration will begin at 8:00 am and the first stop of the tour will be at 8:30 and finish with lunch. To get to the field day area, start at Expressway 83 and go north on Mile 2 West to Mile 10 North. Go about 1/4 mile further north. There will be signs on the left hand side of the road to direct you to parking for the field day on the Hiler Farm Annex. The attached agenda will provide the details of the field day. There will be 2 hours of CEUs provided. We hope all of you can be there. Dryland cotton fields were going down fast with open bolls common throughout the area. Most irrigated fields were also showing some open bolls. The earliest planted of all fields were nearing defoliation. Cotton Defoliation & Weevils And speaking of defoliation; it should include an insecticide for boll weevils. Weevils were lower this year than expected and efforts should be continued to keep it that way for next year as well. And, when stalk destruction through herbicide use is made, add an insecticide for weevil control there, also. This too will aid in further reducing numbers of weevils that will be leaving the fields and trying to find there way into overwintered habitat. Weevils Lower for Good Reasons Boll weevil numbers were lower than expected this year probably because of three factors. The improved stalk destruction in the fall of 2000, the major increase in use of overwintered boll weevil applications and the hot and dry weather. The improved stalk destruction removed much of the old volunteer cotton which could have supported boll weevils in high numbers through the early part of 2001. The increased use of overwintered weevil treatments knocked off weevils moving from overwintered areas to new cotton. And finally, the hot, dry weather conditions killed weevil grubs in squares and small bolls laying on the ground (Some dead weevil grubs were found in small bolls and squares this week).

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Hot Weather Not Sufficient

Some would argue that the hot weather was primarily responsible for the weevil demise. The weather was hot and dry in most of the LRGV in 2000, yet weevils destroyed large amounts of yield across the area. So, the addition of thorough stalk destruction and overwintered weevil applications probably made the difference between last year's weevil numbers and this year's.

Punctures Up in Young Cotton

Boll weevil punctured square counts increased in later planted cotton fields this week. Punctures ranged from 2 to 40 per 100 plants in later planted fields. Most of the earlier planted fields had fewer punctures, ranging in number from 0 to 10 per 100 plants.

Trap Numbers Holding Steady

Boll weevils trapped this week were only slightly higher than last week(See this week's weevil trap line counts). Watch for increasing numbers to go much higher in the coming weeks.

Whiteflies Still Increasing

Numbers of Silverleaf Whiteflies (SLWF) have been increasing, agin this week. Hot and dry weather conditions favor SLWF. Hot weather allows for rapid development and population increases of SLWF. If the weather stays hot and dry watch fields closely for SLWF for the next several weeks, particularly fields with hairy leafed cotton varieties.

Worms Not Bad

Bollworm and tobacco budworm worm counts ranged from 0 to 3 per 100 plants. Damaged squares from worms ranged from 0 to 10 per 100 plants. Continued heat and fast maturation of the cotton crop will likely keep worm numbers low. A long spell of wet weather could change the worm situation for the worse as it would provide much more tolerable field conditions for young worm and egg survival than are currently being experienced.

Beet Armyworms Still Here

Beet armyworms (BAW) moths still were caught in traps around the LRGV this week. Moth counts showed a slight decline over last week's numbers but were slightly higher than the same period in 2000. BAW larvae were not reported from fields, however. Fields which still require an additional 3 to 4 weeks maturation time should be monitored closely for any resurgence of BAW larvae.

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