Texas Agricultural Extension Service

Volume XXVII No. 16 June 18, 2001 GENERAL SITUATION: Rainfall was recorded in several areas of theLRGV as of last Thursday and Friday nights. The highest amounts appeared to be centered around the mid-Valley area with over 2 inches reported there. Elsewhere, rainfall was light and more scattered. Less than ½ inch fell in the dryland areas of Willacy and Cameron counties. High speed winds, some in excess of 60 miles per hour also were reported. The high winds were responsible for knocking more grain sorghum and some corn to the ground. Some cotton plants were also leaning heavily in scattered fields due to the wind. Most of the dryland fields received very little benefit from the scattered rains. Insect activity was holding steady. Fields Maturing Fast Small bolls and large squares were aborting in many more fields this week. The hot temperatures (night time lows of 80+ degrees F and day time highs of 100+ F) along with the crop maturity appeared to be forcing increasing amount of fruit to be shed. Even irrigated fields, which had the most fruit per plant, were losing large numbers of squares and small bolls this week. In fact, in most fields, considerably more fruit was being shed than was being damaged by all insect pests combined. Most Irrigated Fields Look Good Despite the loss of fruit in the irrigated fields, the majority of the irrigated fields looked good this week. Many fields had large bolls near the top of the plants and many more small bolls were obvious throughout the plant canopy. Weather and insect pests permitting, the irrigated crop could produce a decent yield. Now, if the price were right, somebody might make a little money. But, that is too much wishful thinking. Boll Weevils Tough, but Manageable Boll weevil activity, though increased in some fields, was not as heavy in most fields as was expected by this time. Punctured square counts ranged from 1 to 25 per 100 plants in irrigated fields and 0 to 5 per 100 plants in dryland fields this week. Insecticide use on most fields was less than 5 sprays total for the season so far, when we were expecting in excess of 7 or 8 applications by now. Part of the answer probably lies in the very hot and dry weather pattern that was being experienced and part in the number of people who used overwintered boll weevil insecticide treatments this year. This season saw one of the highest uses of overwintered boll weevil sprays in many years, based on comments from producers, consultants and agricultural chemical fieldmen. The impact on weevils from all sources seems to have benefitted most growers' pocket books since so far, this year's cotton crop has been relatively cheap to produce. Of course, with the price paid to producers around 45 cents per pound of lint and the yield potential across the Valley to be less than average, the cost of production has to be much lower to make a profit.

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PEST CAST continued

Boll Weevils Increased in Traps

Boll weevils were caught in higher numbers this week (See attached trap graphs) than in the last several weeks, as was expected. Weevils were beginning to move from field to field searching for a better living. Dryland fields which had begun to dry out and very mature irrigated fields were delivering more weevils into the overall emigration and to traps this week. Increased numbers were noted in several locations around the LRGV this week and likely will go much higher as we proceed to the end of the cotton season.

Beet Armyworms Lower

Beet armyworm (BAW) egg masses in scattered fields and some treatable levels of worms in at least one field in the sugar mill area near Santa Rosa were reported this week. Egg masses did not appear to be turning into large numbers of worms, but the increased numbers of egg masses goes along with the increased moth counts which we reported from pheromone traps the last two weeks. Trap counts this week were slightly lower than last weeks pheromone trap moth captures. All fields need to be monitored frequently for BAW larvae to determine if they have reached high enough levels and are causing enough square, bloom or boll losses to consider treatment. Generally, BAW worm counts should be near 20,000 per acre before treatment while bollworm/tobacco budworm larvae should not exceed 5,000 per acre before

treatment at this stage of the cotton crop. BAW larvae generally start their life cycles by feeding on leaves for at least two to three instars before they move to fruit. Bollworms/tobacco budworms tend to start on tiny squares as soon as they hatch and keep feeding on squares, blooms and bolls throughout their larval stage, thus making them a more fruit damaging pest than beet armyworms.

BAW moth counts from traps went down slightly at all locations across the LRGV this week. This is a typical trend for BAW moths in the LRGV. But, just because they did that last year and the year before is not an excuse to stop checking for BAW worms in the fields. BAW are a migratory species and can move in mass rather quickly. So, stay alert for BAW in your fields.

Beet Armyworm Moth Counts

Bollworms Scattered

Scattered reports of bollworm eggs and larvae were received this week. However, the numbers were low in scouted fields. Egg and worm counts this week ranged from 0 to 6 per 100 plants.

PEST CAST continued

Spider Mites Light

Spider mite infestations seemed to have gone with the wind and rain. The largest mite infestations were observed in irrigated fields. That is also where the majority of the rain fell recently. Thus, the mites were battered severely by the weather conditions. Some infestations could resurge and any field which was previously infested with mites should be checked again to determine if re-infestation has occurred and if treatment is necessary.

Cabbage Looper Moths in Area

Cabbage looper larvae and moths were also noted in many area fields this week. None of the larval infestations were reported to be high, but could go higher if the moths seen in some fields have laid many eggs and any larvae which hatch from them survive beneficial insects and the current weather conditions. Loopers are often seen in the later half of the cotton season in the LRGV and in some years they do require control in selected fields. Be on the watch for increasing loopers.

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