Texas Cooperative Extension Service
The Texas A&M University System
Hub of the Plains
Pest Management Report
A newsletter about integrated pest management for growers in Lubbock, County.
 

(806)747-2625 (phone)
(806)781-4084 (mobile)
(806)762-4178 (FAX)
b-baugh@tamu.edu (e-mail)
http://lubbock.tamu.edu/ipm (web)
http://www.tpma.org (web)
Volume 6- No. 9
1418 Ave. G Lubbock, Texas 79401
Aug 8, 2001

IN THIS ISSUE:

* CURRENT CROP CONDITIONS
* WHAT THE SCOUTS ARE FINDING
* BOLL WEEVIL POPULATIONS INCREASING

CURRENT CROP CONDITIONS
The area cotton crop is continuing on schedule with program fields ranging from 6 nodes above uppermost white bloom to zero. If the current weather conditions remain the same, all program fields will have acquired enough heat units to be safe from weevils and worms by August 23 with the earliest fields acquiring enough heat units by August 10. Currently we are receiving an average of 24 heat units per day, but a cool down is forecasted for the remainder of the week. All program fields will be ready for harvest aid applications by September 17 with the earliest fields being ready by August the 30.

WHAT THE SCOUTS ARE FINDING
Boll weevil trap catches have increased dramatically over the past two days. Egg laying and feeding punctures are increasing in most program fields from Acuff to Lake Buffalo with a high of 3% punctured bolls. Percent punctured fruit in and around the Lubbock city limits are running from 25 to 30 percent total punctures with most being egg laying punctures. Just because you only have 2% bolls does not mean that you are ok. Experience has taught me that the 2% can increase to 15% to 20% in less than six days.

Bollworm eggs are still being found in most program fields and are ranging from 1000 to12000 per acre with larvae ranging from 0 to over 3,000 per acre. Remember, the economic threshold for bollworms is 8000 to 10,000 per acre.

Whiteflies are still being found in fields that are late planted and or stressed due to inadequate irrigation.

BOLL WEEVIL POPULATIONS INCREASING
As mentioned earlier, boll weevil populations are increasing. Red weevils and egg laying punctures can be found in most program fields in Eastern Lubbock County. Because, most of these fields have more bolls than squares, the economic threshold that we are using is 15% to 20% punctured bolls. In most cases the fields that we have treated last week and this week have reached this threshold rather quickly. It is not uncommon to have 4% to 5% punctures and five days later having 20% to 30% punctures. In most cases we have had enough worms to justify the use of a pyrethroid for the first application and are coming back with 16 oz. methyl or 12 oz. of Malathion ULV five days later. You should be warned that the use of a pyrethroid combined with methyl or Malathion ULV can open the door for secondary pest outbreaks.

As you all well know, this crops water bill has been extremely expensive. Weigh the pros and cons of the various pest control strategies (know which products cause secondary pest outbreaks). Cast a shadow on your own fields and check to see if your bolls are mature enough to withstand any insect attack.

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Call your County Extension Agent, chemical applicator and any private consultant that comes to mind and compile as much information as you can.

Suggested Insecticides for control of in-season boll weevils.

Insecticide
Formulated amount
per acre

Guthion® 2L or ULV 2 lb
1 pt
Guthion® 3F
0.57 pt
Sevin® 80S
2.0-2.5 lbs
Phaser® 3 E
1-4 pts
Thiodan® 3E
1-4 pts
Thiodan® 2CO
1.5-6 pts
ULV Malathion
12-16 oz
Methyl Parathion 4E
12-32 oz
Penncap M® 2F
1 pt
Vydate® 2L
1 pt
Vydate® 3.76C-LV
8.5



Mean number of whitefly adults per fifth mainstem leaf down from top of plant. Bobby Harkins Farm. Lubbock County, 2001.
TRT
rate/acre
Pre
8 dpt
%
Control

Centric 40 WG
3 oz
15.00 a
6.4 a
-27.9
Karate Z + Orthene 90S
2.2 oz + 9 oz
22.80 a
3.47 b
54.4
Thiodan 3EC
53 oz
16.70 a
3.83 b
31.3
UTC
20.23 a
6.75 a
----

LSD (P=.05)
NS
2.523
----

P>F (0.0013)
0.1864
0.0846
----

Means followed by the same letter are not significantly different.
Mean number of whitefly nymphs per fifth mainstem leaf down from top of plant. Bobby Harkins Farm. Lubbock County, 2001.
TRT
rate/acre
Pre
8 dpt
%
Control

Centric 40 WG
3 oz
96.63 a
70.72
-21.6
Karate Z + Orthene 90S
2.2 oz + 9 oz
51.72 a
53.05 a
-70.4
Thiodan 3EC
53 oz
81.03 a
24.23 b
50.3
UTC
105.47 a
63.47 a
----

LSD (P=.05)
NS
21.673
----

P>F (0.0013)
0.4257
0.0159
----

Means followed by the same letter are not significantly different.



Brant Baugh
Extension Agent - Integrated Pest Management
Lubbock County



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___________________________________________________________________________________________________________

The Texas A&M University System, U.S. Department of Agriculture, and the Commissioners Courts of Texas Cooperating

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