Hot, generally dry weather is really pushing cotton along at a phenomenal pace where moisture remains adequate. I have observed lots of irrigation pumps running across the area. I guess that the recent reduction in pumping costs and the reality of the need to water cotton if any kind of reasonable yield is to be obtained has encouraged many growers to fire up their irrigation systems. Many fields are now blooming or just now entering the blooming period. As cotton blooms, it is time to get serious about its water needs. Peak water demand occurs during the blooming period when yield is pretty much fixed.

Most fields that are just now blooming are averaging 8 or more nodes above white flower (NAWF). This is a better situation than last year when many cotton fields cutout prematurely (NAWF=4-5). If producers don't keep up with the crop's water needs, cutout will approach rapidly.

There have been some problems with square retention, especially in certain areas northwest of Lubbock. Thus far it appears that several varieties are implicated. The agronomists and plant physiologists tell us that a cotton plant holds very tightly to squares and sheds most of it's fruit in the flower or small boll stage. They also tell us that if squares are shed, the most likely cause is due to insects such as fleahoppers and plant bugs. Small caterpillar pests such as bollworms and beet armyworms can also cause square shed.

After watching after cotton insect problems for 25 years, I have come to the unsubstantiated conclusion that there are several other factors that can cause square retention problems. After all, if you can't find enough square-stealing insects to blame, there just has to be other causes. There are probably environmental events that can cause square retention problems such as hot, desiccating winds, sand blasting, and maybe even wide swings in temperature. I have often wondered that if cotton plants go through an early period of adversity where growth is held in check, leaf area is reduced (heavy thrips and wind damage) and root development is suppressed; if these plants don't have trouble with early square retention. We all know that poor water management and low nitrogen fertility can likewise cause square retention problems. We also know that Roundup applications do not cause square shed.

Finally we get to the issue that certain varieties appear to be more prone to square retention problems than others. In other words, these particular varieties often are more sensitive to environmental adversity.

Many of the squares that are being shed are pinhead-sized and therefore within the size range that fleahoppers could damage. Still others are matchhead or larger in size and well outside of the size range that fleahoppers can damage. If these larger squares are still present they often are light yellow in color. If only a square scar is left, then these scars are 1/16^th to 1/8^th inch in diameter, too large to have been left by a shed pinhead-sized square. I have also noticed that much of this square shed has occurred at least 5 days prior to my inspection. This could mean that whatever was causing square retention problems may be over.

Problems with square retention. I've already addressed some of the issues pertaining to square retention problems in the General Situation section above. While I think much of the problem lies outside the realm of cotton entomology, there certainly have been fields with fleahopper problems over the past 3-4 weeks. Most fields have avoided problems with this pest. This is good news so far since we were expecting increased problems with fleahoppers this year because of our earlier, above average winter and spring rainfall amounts.

Fleahopper-infested fields can have either an acute problem or chronic problem. Acute problem fields are easier to identify but square set often falls below acceptable levels before corrective measures can be applied. These are the fields with a drop of 15-25% in square retention and 20-50 fleahoppers per 100 plants present. Most fleahoppers found in these fields have been wingless nymphs. This makes careful plant monitoring even more critical. Otherwise a scout could miss the cause of the excessive shed. Twice-a week scouting will often locate these fields before significant square retention problems appear.

Chronic fleahopper infestations are more difficult to address since they develop over a period of 2-3 weeks with fleahopper numbers never reaching trigger levels. A field with this type of a problem might have 87% square set the 1^st week with 15 fleahoppers per 100 plants, 79% set and 12 fleahoppers the 2^nd week and 68% square set and less than 20 fleahoppers the 3^rd week. This field definitely needed treatment after the second week. Remember, I'm only talking about square sets involving first position squares.

If there are not enough fleahoppers present to tie to most of the cause of excessive square loss, then an insecticide application will not solve the problem, will be an unnecessary expense, and could remove enough beneficial insects and spiders to cause a flare-up of aphids, bollworms or beet armyworms.

Second generation of beet armyworms (BAW) held in check. We continue to observe egg masses and small BAW caterpillars in many cotton fields, especially northwest of Lubbock, but most of these infestations have failed to establish at damaging levels. The activities of spiders, big-eyed bugs, minute pirate bugs and damsel bugs have not allowed many of these caterpillars to survive. As cotton begins to bloom, host plant conditions improve for BAW survival and infestation levels may drift upwards in spite of "beneficial" activity. There have already been a very few fields reported by consultants in which BAW caterpillars have moved from leaf feeding to damaging squares. These infestations will need to be addressed quickly if square loss is excessive and their numbers approach bollworm thresholds.

Most of these early infestations will appear in fields as they begin to flower and are of the chronic, not acute type. A "nickel and dime" damage pattern is established where caterpillar numbers never reach treatable levels. My strategy for the period that runs through the second week of bloom is to watch square damage, scout twice weekly and if square retention falls below 65% and/or my combined caterpillar number for two scouting periods equals or exceeds 8,000-10,000 per acre, then I will spray. While pyrethroids are very cheap now, they still flare aphid infestations and remove "beneficials" for 3-7 days longer than other classes of insecticides. I would consider using products like Larvin, Tracer or Steward. If lots of ladybeetles are present then I would rule out the use of Steward.

Part of the cause for lower trap catches is the presence of a squaring or blooming cotton crop. Traps are less attractive to weevils than these fields. These low weevil numbers in fields are difficult to find but could produce significant numbers in two generations prior to the planned September 1 start of the diapause program of the TBWEF in both the Southern High Plains/Caprock and Northern High Plains zones.

Natural enemy numbers continue to build. I am astonished at how many "beneficials" are present in our fields for this time of year. Crab spiders continue to dominate the scene with minute pirate bugs, damsel bugs and big-eyed bugs coming on strong. I think the continued presence of lots of thrips has provided an abundant food source and fostered these high predator numbers. Now if we can only keep them in our fields and not do anything foolish to kill them prematurely!