Overwintered boll weevil emergence continues as the first summer generation of adult weevils begins to appear in earlier planted fields. There is a real danger for rapid increases in punctured square counts if fields are not scouted closely and frequently. This is turning into a real "wormy" year. Armyworms, both beet armyworms and yellow-striped armyworms, have blossomed across the area and are causing a real concern as their numbers approach or exceed our treatment levels. The extended bollworm egg lay has taken an upward turn with infestations appearing in most fields outside the influence of corn. Fields with both armyworms and bollworms will need to be treated differently than where either species is found alone. Control could be quite expensive, especially if infestations continue through August and into September.

Aphids have not yet become a factor but will become a problem as more insecticide goes out against these caterpillar pests and weevils. The Eradication Foundation is beginning to adjust trap triggers as more beet armyworms pop up across active zones. These same infestations are being found outside of active eradication zones as well.

Second generation southwestern corn borer egg lay has commenced. Scouting efforts should be redoubled to avoid losses due to tunneling and later lodging. Corn borer control decisions must include consideration for spider mites and rootworm adults.

Sorghum remains relatively pest free at this time. Some fields have developed sorghum ergot as evidenced by sticky deposits not associated with aphid infestations. Watch out for the armyworms.

Heavy flights of sunflower moths continue in some areas. A single insecticide application may not be sufficient where flowering is not uniform in timing across the field.

Cowpeas have come under attack from beet armyworms, yellow-striped armyworms and another unidentified caterpillar. Infestations are heavy in some fields.

It is time to think about nitrogen fertilization needs of sorghum. Recent rains have bolstered yield prospects but additional nitrogen may be needed to optimize yield.

Hot, dry weather had been the rule for the last several days raising hopes that pest mortality would increase. It has appeared not to have increased. And with the return of some fairly widespread showers Wednesday and Thursday, survival chances should remain high. And to make matters worst, the recent warm weather and good moisture conditions have resulted in the rapid development of a plant canopy that provides shade and relief to insects from hot daytime conditions. Worms and weevils are taking advantage of these improved conditions and are popping up like weeds across the area. Fleahoppers and plant bugs are also becoming a problem in selected fields. And aphid numbers are increasing where overwintered boll weevil applications were made both inside and outside active eradication zones.

Worms ‘Duking It Out" With Weevils For Squares

A significant increase in bollworm activity has occurred since this past weekend. Infestations are highly variable from field to field and area to area but have often reached levels requiring quick control decisions. This latest bollworm cycle is heavier and earlier than usual. Square retention has often plummeted where significant worm activity has been encountered.

While previous infestations were generally of the chronic "nickel and dime" type, this new wave has pushed caterpillar numbers as high as 80,000 per acre in a limited number of cases. But even the "nickel and dime" infestations had gone on long enough to warrant treatment in many instances. But these new infestations are now in the 8,000 to 22,000 range in many instances and must not be ignored. Beneficial arthropods we have been trying to conserve during our first run in with boll weevils will be insufficient to hold these numbers back with the expected lower weather related mortality (pictures of beneficial arthropods).

Where bollworms are the only pest of concern; Tracer, Steward or Denim may be the materials of choice (at least where there is a concern about flaring aphids or preservation of beneficial insects). These are not cheap but few insecticide options are any more. They also do not provide pyrethroid type control (slower acting, lower residual activity and less efficacy). Steward is also pretty hard on lady beetles. Denim is quicker acting than Steward, Intrepid or Tracer with all its control exhibited in 4-5 days. The other materials are slower acting and don’t really express all their control until 4-5 days or later after application. That is why Denim is popular with some consultants as it allows for a quicker retreat evaluation. Intrepid simply will not be any good on bollworms with less than the 0.35 pounds ai/acre rate. Too expensive for most folks. But it is excellent against armyworms at the 0.1-0.15 rate.

To achieve any decent level of control with these materials will require higher rates and often two shots for every one that would have been made with a pyrethroid. You must also expect a reduced level of control. Now I know that most of you want a "clean" field if an expensive insecticide is to be used. This is not necessary since all we really need to do is reduce numbers below the economic threshold. But I also understand your concern. Also realize that the higher rates of even the more selective materials will have an adverse effect on beneficial arthropods. And the pyrethroid alternative could result in the additional expense of aphid control later on.

If you are not concerned about flaring aphids and are after a cheap remedy, then Ammo could be the correct choice. It is one of the cheapest pyrethroids, but is not the best one where boll weevils or plant bugs are concerned. But once beet armyworms (BAW) enter the picture another list of insecticides must be considered. Pyrethroids are out but Tracer remains a viable option. Add to this Intrepid, Denim and Steward where beet armyworms are in the mix with bollworms. Denim, Steward and Intrepid can not be used to target bollworms alone since the section 18 provisions authorizing the use of these chemicals are for BAW’s, not bollworms. Use the higher rates where bollworms are a factor.

Where bollworms and beet armyworms are in the targeted mix, there is another possible management alternative. Instead of two high rate applications of one of the newer non pyrethroid materials, consider a mixture. Use a low rate of a pyrethroid with a low rate of Denim, Tracer, Steward, or Intrepid. This would be cheaper than two applications of these newer materials and would provide more satisfactory results. These newer materials are excellent BAW materials but will not control the larger caterpillars like Pirate could (expect 45-65% control of lager worms).

Beet Armyworms Marching Across the Area

Beet armyworm (BAW) infestation activity is also on the increase, and in many of the same fields that are now experiencing bollworm problems. There are also yellow-striped armyworms and a yet to be identified caterpillar mixed in with many of these BAW infestations. While the epicenter of BAW activity may still be in the Western Eradication Zone, it has spread to other areas of the High Plains as well. Spraying for BAW’s has been recently reported from Gaines, Terry, Yoakum, Crosby, Cochran, Hockley, Lubbock, and Lamb counties. Thus far it is still difficult to make a direct connection between eradication program sprays and increased BAW problems. Keep in mind that some fields have received multiple overwintered boll weevil applications even outside of active eradication zones. Even though the insecticides used are often "softer" on "beneficials" and therefore less prone to trigger secondary pest outbreaks, multiple applications can lead to the same result as the ULV malathion treatment program.

Satisfactory control of beet armyworms is a matter of timing. Wait until the caterpillars are 1/2 inch or larger and you will have to resort to throwing rocks. Insecticides cleared through full labeling or section 18’s include: Confirm, Lorsban, Intrepid, Denim, Steward and Tracer. Pirate is not available but would have been handy to have in those situations where the infestation "gets out of hand". Confirm should be reserved for those instances where infestations are well within the treatment guidelines and worms are small. Intrepid is a "beefed up" version of Confirm and can do a little better on BAW and a lot better on bollworms. Denim, Tracer and Steward have similar efficacy against BAW and provide some control of bollworms. Steward would provide pretty good control of the western tarnished plant bug but not as good as a pyrethroid or maybe even Orthene.

Square Retention Drops in Some Instances

Square retention levels have fallen in many fields this past week. While insects are easily targeted for taking the blame, the general absence of significant fleahopper or plant bug infestations in most cases lends little support to this scenario. There are certainly fields with recent increases in either fleahopper or plant bug activity, often associated with prime sources for these insects (such as alfalfa for plant bugs) but for the most part, damaging pest numbers are missing. We have gone through some pretty significant weather events that sometimes can lead to excessive fruit shed in some instances. Several cool and cloudy days can certainly exacerbate the situation.

One variety that continues to rise to the top of the list is PM2200RR. Most complain about poor square set or excessive square shed involving PM2200RR but are not exclusive to this variety. Our thrips tests in the Lazbuddie area were planted with this variety and are now exhibiting a square retention problem in the 2nd to 5th primary squaring positions. This was not due to thrips control practices nor to any plant bugs or fleahoppers (hard to find them). It may be that PM2200RR is more environmentally sensitive than other varieties. More data is needed. Does the company have this data.

For those situations where fleahoppers or plant bugs could be the source of the retention problem, fields must be scouted closely and frequently. A cotton field near alfalfa may have 1-2 adult plant bugs per 3 feet of row and 85% square retention going into the 3rd week of squaring only to have square retention fall to 65% or less in one week. Lygus (plant bugs) can be sneaky that way. The above situation would have made me extremely nervous and I would have treated the cotton with a pyrethroid?

Boll Weevils Circumventing Traps

Punctured squares are being found in increasing numbers in some fields, even in active eradication zones. Traps have failed to trigger either an eradication treatment or a producer-applied treatment outside of active eradication zones. What gives? Except for the dryland crop, our irrigated crop got off to a fast start before late cool, rainy weather slowed things down for awhile. But we did begin squaring early in many areas, distracting weevils from traps and drawing them into fields. Once a cotton field is in the second week of squaring or a significant portion of the acreage around a subject field is squaring, traps are no longer a reliable decision aid for overwintered boll weevil control. The extended emergence and earlier squaring crop really messed things up!

GRID traps still continued to capture high enough numbers to indicate that we have yet to come off the current plateau of emerging overwintered boll weevil activity (Table 1). This represents a peak of extended emergence of at least 5 weeks! Table 2 makes a clear case for this extended emergence but also shows that 1999 was a year of extended emergence as well. In fact, in reviewing emergence cage data from the Lynn Forrest farm in Horseshoe Bend Canyon behind Slaton the last three years shows that emergence extended for 4 weeks in 1998 and 5 weeks for both 1999 and 2000 (assuming peak emergence ended last week).

Winter survival for these last three years ranged from 15.5% in the 1997/98 winter to 21.5% after the winter of 1998/99. Emergence may not be over for this year as yet but so far survival is at 17.3%. The survival in all three years was significantly high and 10-15% higher than we would like to see. Extended emergence is often associated with mild winters. These emergence studies are a product of a research program conducted by Dr. Don Rummel (Experiment Station Entomologist, retired) and Stan Carroll (Experiment Station Assistant Research Scientist).

Last week’s GRID trapping results are given in Table 3. For the most part, catches have lagged behind somewhat in inactive zones compared to last year at this time. I still think this is mainly due to the earliness of the crop and not a significant change in weevil numbers compared to last year. Weevil number reductions in active eradication zones are still looking good considering the weather conditions we have experienced the last 7 weeks. Best reduction is in the Western Zone followed by the Permian Basin and then the Northwest Zone. The lower percent reduction observed in the Northwest Zone is probably an artifact of low numbers to begin with. Gaines County shows the greatest reduction while Crosby, Floyd and Garza counties show the highest catch levels.

Once traps can no longer be used as decision-aid tools, you must scout fields for punctured squares. When third-grown squares are present, pull 100 of these or larger squares and examine for punctures. If 20% of these are punctured, the field needs to be treated one or more times depending the actual level for the field. If scouting a field prior to third-grown square appearance, 10-15% punctured squares would be my threshold. The key to this business is to track the field’s record. If punctured square counts are increasing but not yet at threshold and you won’t check the field for another week, things could get real dicey. Common sense must prevail. Shorten your scouting interval or spray on a more aggressive threshold.

First summer generation weevils are just now beginning to appear in the earlier colonized fields. These red weevils will mate in a few days and square damage can rapidly increase after this. The bulk of this first summer generation should not be out until later this month.

Table 1. Total boll weevils caught per week and percent of traps catching boll weevils since April 24, 2000 in the GRID trapping program.*

Week beginning	Total weevils caught	% of traps catching weevils
April 24	948	30
May 1	887	34
May 8	5243	67
May 15	1112	34
May 22	2106	45
May 29	1651	46
June 5	4163	56
June 12	3391	47
June 19	5684	49
June 26	3346	53
July 3	3318	48

*Includes three counties in the Rolling Plains

Table 2. Comparison of average weekly boll weevil trap catch in the Southern High Plains/Caprock Zone between 1999 and 2000.*

Week beginning	1999	2000
June 5	12.2	6.8
June 12	7.8	6.1
June 19	9.9	4.1
June 26	9.5	6.0
July 3	3.3	4.6
July 10	2.0
July 17	2.1
July 24	2.0
July 31	5.8
August 7	5.5
August 14	13.7

*These data represents the average number of weevils caught per trap catching weevils. Zeros are not counted.

Table 3. Week 27 — Accumulative average number of boll weevils caught per trap in the GRID trapping program starting with week 18.

Location	1999	2000
Northwest High Plains	36.0	16.3
Northern High Plains	62.9	53.3
Southern High Plains	91.2	56.9
Western High Plains	190.3	23.7
Permian Basin	94.0	26.4
Andrews	169.2	25.9
Bailey	39.8	16.7
Borden	65.6	43.0
Briscoe	70.7	62.4
Castro	11.9	6.0
Cochran	68.2	57.9
Crosby	120.0	102.2
Dawson	124.6	42.3
Deaf Smith	8.0	1.0
Floyd	48.0	86.0
Gaines	242.0	21.0
Garza	169.7	122.0
Hale	54.8	52.5
Hockley	522.8	31.1
Howard	97.8	20.2
Lamb	38.7	16.2
Lubbock	66.5	49.5
Lynn	73.6	31.1
Martin	44.6	13.0
Midland	35.3	14.7
Parmer	8.9	4.0
Swisher	56.2	39.4
Terry	125.5	20.7
Yoakum	159.7	22.0

These data represents the average number of weevils caught per trap catching weevils. Zeros are not counted. Refer to the Plains Cotton Growers, Inc. web page for actual total numbers caught and percent of traps catching weevils each week.

Eradication Update

The Texas Boll Weevil Eradication Foundation is keeping the heat on emerging overwintered boll weevils in the hopes that mid season applications can be kept to a minimum. According to Program Director, Charles Allen, their goal is to spray less than 10% of the acres in any one application week. Through July 9, the Foundation has treated approximately 350,000 acres in the Northwest Zone, 338,800 acres in the Western Zone and 69,700 acres in the Permian Basin Zone. A significant portion of this accumulative sprayed acreage was treated last week. Beet armyworm trap catch activity is variable with numbers about the same as last week in the Western Zone (44/trap), down in the Permian Basin Zone (35/trap) and up significantly in the Northwest Zone (108/trap). Beet armyworm infestations have increased in size and scope since last week, a fact that has not been ignored by the Foundation. Dr. Charles Allen personally conducted a survey of 142 fields in the Western Zone noting that the heavier activity was in the dryland crop as well as the younger crop. On the basis of this survey, the Foundation has increased the trap trigger from 2 weevils per 40 acres trapped to 3 per 40 acres trapped in selected work units near Brownfield, Seagraves and Plains. This will be the approach of the Foundation to selectively change trap triggers so that eradication pressure can be kept on fields in areas where the secondary pest threat is low and backed off where there is a possibility of enhancing a secondary pest problem. The Foundation will continue with a weekly survey in the Western Zone and will expand this into other zones as the need arises. Please keep the Foundation appraised of your situation so that problems don’t sneak up on us.

Cotton aphids can no longer be overlooked. With the extended emergence of overwintered boll weevils and the necessary insecticide applications to address this both inside and outside active eradication zones, aphid numbers are generally on the increase. Cotton fields are also more prone to develop aphid problems once they begin to bloom. Beneficial arthropod levels are generally low and recent caterpillar problems and insecticide applications needed to address problem fields could precipitate a rapid buildup of this pest in some areas. We have Furadan 4F available through a section 18 in Texas but it has not been triggered in any area of West Texas. Do realize that we already have some pretty good aphid control materials with Provado, Bidrin and even Lannate when used at the appropriate rates, proper coverage, and when applied at the right point in the development of the infestation. JFL

Conditions have been very favorable for crop growth over the last week. Heat unit accumulation has returned to near normal, with an average of about 23 per day at Lubbock for the past few days. The record June rainfall has resulted in a very lush crop thus far into the season. Additional rainfall has been obtained in some areas over the last couple of days. As of this writing, reports from Lubbock range from 0.1 inch (my house) to 1.45 inches at the airport. Other areas, including about 1 inch at Abernathy, 0.5 inches at Morton and Friona, 0.4 inches at Muleshoe, and 2 inches at Tulia. Crop growth continues to be phenomenal in many areas, resulting in plants and leaves that are larger than what is normally observed in the High Plains at this time. Many earlier planted fields are now blooming with small bolls present, while the late planted crop is into early squaring. The lush cotton is being targeted by several caterpillar pests, boll weevils, and plant bugs; and should be carefully watched.

Square Retention Issues

Between boll weevils, various caterpillar pests and plant bugs, we need to keep a careful watch on the fruit retention in fields. Significant small square shed has been observed in some fields. Paymaster 2200RR has been reported to have low retention in some areas north of Lubbock. Square shed caused by various environmental problems is difficult to determine, but shading due to dense plant populations and general poor growing conditions in late June and early July may be partly responsible. Small square shed is not unheard of, and may be more problematic with some varieties than with others. The relative sensitivity of fruit shed decreases with square age, but after pollination rapidly increases. Generally speaking, a boll that reaches 14 days of age seldom sheds due to physiological reasons.

Some questions have again been asked concerning the possibility of small square loss arising from late over-the-top Roundup Ultra applications after the 4-leaf cutoff stage. I covered this last week, but will again emphasize that problems with late Roundup applications are related to poor pollination causing so-called parrot beaked bolls and possibly subsequent boll shed, not small square loss. With our lush cotton and high humidity, we have very little "barking over" of cotton plants in most fields. This situation may likely contribute to increased yield problems with "salvage applications" this year. Of course one has to factor in weed population effects on yield, the "harvestabilty" of the field due to large weeds, etc. into an "economic analysis" of each field-specific situation.

Roundup Drift Problems on Conventional Cotton Varieties?

Roundup herbicide drift onto conventional cotton has resulted in a considerable number of calls and reports across the area. High winds during closure of the over-the-top window resulted in a lot of drifting of Roundup onto nearby conventional varieties. Cotton with "stacked nodes" and reddening of leaf petioles is generally an indication (images of Roundup effects on cotton). What concerns me is the fact that at least one field that I looked at in Crosby County had relatively uniform problems (i.e. it was not just confined to around the edge of the field). Many plants exhibiting these symptoms were simply not growing, and had no visible squares. The probability of obtaining any reasonable yield from these type plants is very low, based on the calendar date and "normal" fall temperatures. In a planting of a conventional variety adjacent to Roundup Ready cotton in a research project at Halfway, Roundup drift caused the entire area planted to conventional varieties to have fairly uniform symptomology. Only a few "normal escapes" were visible. These "normal escapes" may not have obtained enough drift to cause problems, or may have had contamination of Roundup Ready seed into the conventional variety during harvesting and/or processing or planter box cleanout.

Watch the video: Scouting For Second Generation Southwestern Corn Borer.

Eggs are laid singly or in masses of two or more. Initially they are a creamy white, but develop red bands as they mature. It takes approximately five days for eggs to hatch. Unlike first generation (where larvae spend considerable time feeding on leaves), second generation larvae feed in protected areas such as leaf collars, ears, and beneath shucks of the primary (and sometimes secondary) ears. Older larvae bore into the stalk. Eventually, this overwintering generation will girdle the base of the plant and tunnel down inside the stalk. Girdling can cause severe losses from lodging, and the tunnels themselves can reduce the plant's ability to fill ears.

The current economic threshold for insecticide application is when 20 to 25 percent of the plants are infested with eggs or newly hatched larvae. However, with corn prices so low, the 2000 threshold may be higher, perhaps 25 to 30 percent of plants infested with eggs or newly hatched larvae. As with most things at the economic/biological interface, there is no hard and fast magic number here. Things get a little more complicated because Banks grass mite numbers are building in some area fields and corn rootworm adults are pruning silks. Control decisions for SWCB and rootworm adults should be made in consideration of the possibility that some pesticides are capable of "flaring" mite infestations through reductions of natural enemies. Insecticide lists and characteristics are provided in several publications including "Managing Insect and Mite Pests of Texas Corn" (Texas A&M) [http://entowww.tamu.edu/extension/bulletins/b-1366.html], "Pest Management Guide For Corn" (Univ. of Nebraska) [http://ianrwww.unl.edu/ianr/entomol/pmguides/pmguides.htm], and "Insect Pest Management For Field Corn" (Kansas State Univ.) [http://www.oznet.ksu.edu/library/ENTML2/Mf810.pdf]. RPP

For more information, please read, "Sorghum Ergot, Field Identification" [http://agpublications.tamu.edu/pubs/eplant/l5180.pdf] and "Sorghum Ergot, A New Disease That Threatens The Sorghum Industry" [http://agpublications.tamu.edu/pubs/eplant/l5179.pdf].

Many of the grain sorghum acres on the South Plains were planted after the rain stopped in June. In some cases sorghum was planted after damaged cotton. The standard nitrogen (N) recommendation for grain sorghum in Texas is 2 pounds per acre of elemental N for each 100 lbs. per acre of grain production expected. Thus a 4,000 lb. grain yield would need about 80 lbs. of N per acre. That includes both soil and fertilizer N. Nitrogen is by far the most important nutrient for sorghum to maximize sorghum production. Nitrogen is normally used by plants for chlorophyll and protein production, which in turn is used in formation of new plant cells. The seed also stores N to enable early growth after germination. Almost 60% of the N absorbed by the sorghum plant may be found in the grain at harvest. For maximum yields relative to the available water, N should not be lacking or grain development will be reduced.

For some late-planted sorghum production (emerged June 25 or later), it is not too late to make limited side-dress N applications, which should be made by about 3 weeks after emergence. Sorghum re-planted on cotton ground that received N may not need additional N, and knifing in N to buster-planted sorghum is more difficult to place for ready access by the roots. Later applications more than 3 weeks after emergence, risk excessive pruning of feeder roots. But more importantly, developmental potential of the grain head is determined 30 (short maturity) to 40 days (long maturity) after emergence. This time frame, when growing point differentiation occurs, is about 1/3 of the way between germination and physiological maturity for most varieties.

Growing point differentiation is when the first of three components of yield potential in sorghum is determined, that is, the number of spikelets which can bear grain is set. Good N fertility (and water!) prior to differentiation will enable the plant to set more spikelets. Nitrogen stress during this period will greatly influence yield. The two other components of yield potential in sorghum occur at flowering (seed number) and grain filling (seed size). If irrigating, be sure to begin watering in the boot stage just ahead of head exertion and flowering.

Under center pivot irrigation, N fertilizer may be applied several times during the early part of the growing season. Because N is relatively mobile in the soil, N fertilizer placement is not as critical for N as it is for most other nutrients. Producers with late-planted sorghum and good moisture have a good opportunity to recoup N fertilizer and application costs in higher yield. Consider the yield potential of each field and set your sights accordingly for possible N fertilizer applications if the sorghum is still a week or more from growing point differentiation. If you are unsure about the length of maturity of your particular sorghum variety, consult your seed dealer for help in determining when growing point differentiation may occur. CT

To summarize, there was an unusually high incidence of fields with seedling disease in 2000. The most common fungal pathogens were R. solani and Pythium species, which accounted for over 1/2 of the cases where cotton plants were growing poorly and dying. Our current cotton varieties are not resistant to these fungi, but are usually protected by the fungicides applied on cottonseed. The cool, wet conditions occurred after the fungicides had already lost activity, resulting in widespread seedling disease. TW