Crop Situation: The Weekly Weather and Crop Report for the week ending August 4 indicated that 5% of the crop had open bolls, which is 2% ahead of the 5-year average for this time. Statewide temperatures for the week of July 29 through August 4 were 1 degree above normal and average statewide rainfall was 0.14 inches above normal.

Insect Situation: With bolls beginning to open in the earliest fields, it is important to keep in mind that treatment thresholds are higher once the crop enters cutout, reaches NAWB =5, and there are a lot of fields that are beyond NAWB = 5. The budworm/bollworm threshold increases to 8 larvae per 100 plants on both Bt and non-Bt. However, in Bt fields only larvae that are at least 1/8 of an inch long should be counted. Bollworm numbers are down throughout the state, which means that most Bt fields will probably not require another bollworm treatment this season. However, beet armyworms, fall armyworms, and loopers are becoming more common, and some late maturing fields will likely require treatment for some of these caterpillar pests. A few fields in the southern part of the state have already required treatment for fall armyworms. Plant bug numbers are on the increase, especially in the Delta. Although tarnished plant bug is the first pest from which maturing cotton becomes safe from injury (around NAWB = 5 + 300 DD60s), high populations of plant bugs can cause significant injury to that last populations of pickable bolls just before they reach this stage. Problems with stink bugs have been less than anticipated so far this season, but the most critical time for this pest is still to come. High numbers of stink bugs can move into cotton fields, or parts of cotton fields, as they move from maturing soybeans. Most fields probably won’t have a problem with stink bugs this year, but you don’t want to overlook those that do. Clouded plant bugs are more common than usual in the northern portion of the state. This insect can damage both squares and bolls, and treatment thresholds are similar to those for tarnished plant bugs or stink bugs. Treatments recommended for tarnished plant bugs or stink bugs should provide control of clouded plant bugs.

Those Little Brown Moths: There are two different species of small brown moths that are occasionally seen in large numbers in cotton fields. Both of these moths are ½ inches or less in length and tan or light- brown in color. Neither of these is a serious pest of cotton, but because of their numbers they often generate attention and comments. With the help of Mr. John Strider we collected several of each species in Tallahatchie County during late July and asked our taxonomist, Dr. Richard Brown, to identify them.

One species was identified as Achyra rantalis, or the garden webworm. This moth belongs to the family Crambidae, which is the same family as European corn borer and southwestern corn borer. However, these moths are much smaller than either of the corn borers. This quick-flying moth rests with its wings folded almost parallel to its body, so that its at rest wing span is only about ¼ inches, and total body length is ½ inches or less; overall it has a distinct triangular shape. The larvae feed primarily on legumes and a variety of weedy plants, including pigweed. Cotton is also listed as a host, but the larvae are much more commonly found on weeds growing in cotton fields. The larvae are yellow with black spots, and as their name implies, they spin webbing over the plants and then skeletonize the leaves enclosed in this webbing.

The other species was identified as Calothysania amaturaria. This moth has no common name, but belongs to the Geometridae, or inch worm, family. This moth also is only about ½ inches long, but it rests with its wings more perpendicular to its body, giving it an at rest wing span of ¾ to 1 inch. The margins of the wings have a wavy, irregular shape, and there are usually a couple of dark wavy bands running across the wings. The larvae feed on weeds such as dock and smartweed.

Weevil Watch: As the crop enters cutout and square count declines it becomes easier to detect squares or bolls that have boll weevil egg laying punctures. It is also easier to spot adult weevils that may be resting in white blooms. Any evidence of in-field boll weevil activity should be reported immediately to boll weevil eradication personnel.

2002 Plant Bug Efficacy Trial: Table 1 presents the results of a tarnished plant bug efficacy trial that was recently completed in Sunflower County. Treatments were applied on July 26 using a CO2-powered backpack sprayer calibrated to deliver 9.5 gallons of finished spray per acre. The crop canopy was open and conducive to good spray coverage. No adjuvants were added to any of the treatments. Plots were rated at 3 and 7 days after treatment by examining 25 plants per plot and visually searching for nymphs and/or adults in blooms and inside the bracts of large squares. The primary objective of this trial was to compare the performance of the newer neonicotinoid treatments: Centric, Inturder, and Trimax, to that of standard plant bug treatments: Bidrin and Orthene. Thanks to Mr. Richard Horne and Lee Simmons for helping establish this trial. Because they are much less mobile, nymphs are the best stage to consider when evaluating tarnished plant bug efficacy trials. Note that all treatments provided significant reductions in numbers of both adults and nymphs. However, no treatment reduced this heavy plant bug infestation to below threshold levels with just a single application. These results underscore the need for making at least two successive treatments approximately 5 days apart when attempting to control heavy infestations of tarnished plant bugs. Nymphs are especially difficult to control because they spend much of their time feeding inside square bracts where they are difficult to reach with foliar sprays.

Table 1: Small Plot Tarnished Plant Bug Efficacy Trial, Sunflower County, 2002

Treatment	Lbs. Ai. Per acre	Avg. No. TPB per 100 plants *
		3 DAT		7 DAT
		Adults	Nymphs	Adults	Nymphs
Untreated	--	44 a	72 a	61 a	59 a
Bidrin 8E	0.4	20 b	9 c	15 b	18 cd
Bidrin 8E + Trimax 4SC	0.25 + 0.031	17 b	16 bc	18 b	11 d
Trimax 4SC	0.047	16 b	27 b	21 b	30 bc
Centric 40WG	0.05	17 b	15 bc	18 b	12 d
Intruder 70WP	0.05	12 b	23 bc	25 b	32 b
Orthene 97SP	0.5	18 b	7 c	14 b	9 d
Vydate 3.77	0.33	19 b	11 bc	14 b	27 bc

* Numbers within a column that are followed by the same letter are not significantly different (P > 0.1).

Pest of the Week: Loopers: Soybean Looper: Pseudoplusia includens

Cabbage Looper: Trichoplusia ni

Two species of loopers attack cotton in Mississippi. These are the soybean looper, Pseudoplusia includens, and the cabbage looper, Trichoplusia ni. Both species are occasional late-season pests that rarely cause serious economic loss.

Biology: The soybean looper does not overwinter in Mississippi, but migrates in from more southerly areas each year. Cabbage looper, on the other hand, does overwinter in the state, and as its name implies, is a pest of cabbage and other cole crops, as well and cotton and soybeans. Both species deposit their eggs individually on the undersides of leaves. These eggs hatch in three to five days. The larvae, which are strictly leaf feeders, take approximately 14 days to reach the pupal stage. The pupae are attached to the undersides of leaves and are covered with thin, transparent webbing, or cocoon. The adults emerge in approximately seven days. Loopers are attacked by a large number of predators and parasitoids, as well as by several important fungal and viral diseases.

Damage: In both species feeding is confined to leaves and other foliage. When numbers are high, caterpillars may consume the bracts of squares and bolls, but direct feeding on the fruit itself is rare. Thus any damage caused by loopers is "indirect damage" due to premature defoliation. Low levels of defoliation (less than approximately 20%) cause no adverse effects, and it is commonly believed that excessively thick canopied fields may actually benefit from low levels of late season defoliation by loopers, due to improved air movement and reduced boll rot. However, excessive defoliation that occurs before the last harvestable bolls are fully mature can adversely affect both yield and quality of lint. Because they rarely build to damaging levels until very late in the season when many bolls are already mature, loopers do not have the potential to totally destroy a crop, like many other cotton pests. However, heavy infestations of loopers can completely defoliate a crop within just a few days, and this can cause several hundred pounds of yield loss when it occurs in fields that are some weeks from maturity.

Yield Effects: Over the past five years estimated statewide yield losses attributed to loopers have remained consistently below 0.1%, and there have been no catastrophic statewide outbreaks of loopers. However, premature defoliation of late maturing crops can cause several hundred pounds of yield loss in individual fields. Late maturing fields are more vulnerable to damage by loopers than early maturing fields.

Control: Looper populations are normally held in check by the large array of predators and parasitoids. Heavy insecticide use can destroy these beneficial insect populations and increase the potential for looper outbreaks to occur, especially if the insecticides being used do not have activity against loopers. When outbreaks do occur they often crash quickly due to epizootics of fungal or viral diseases that attack loopers. When making looper treatment decisions, it is important to be aware of the potential for these disease outbreaks because, when they occur, they can preclude the need for insecticide treatments. However, because heavy infestations of large caterpillars can defoliate a crop so quickly, insecticide treatment is sometimes required to prevent excessive defoliation. Loopers can damage Bt cotton, as well as non-Bt. Treatments recommended for control of loopers are listed in Table 11. Because soybean loopers are the more common species in cotton, and because soybean loopers are more difficult to control than cabbage loopers, insecticides are recommended based on their efficacy against soybean loopers.

Table 11: Insecticides Recommended for Control of Loopers

Insecticide	Trade Name	Lbs ai/acre
Indoxacarb	Steward	0.09 - 0.11
Methoxyfenozide	Intrepid	0.06 to 0.1
Spinosad	Tracer	0.067 - 0.089
Thiodicarb	Larvin	0.60 -0.90

Source: Cotton Insect Control Guide, 2002, Publication 343, Mississippi State University Extension Service

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Delta Counties – Gordon Andrews: The majority of the fields observed were at Node Above White Flower 5 (NAWF5) and many had accumulated 350 DD60’s passed NAWF5. The only scouting, which should be required in fields, which have cutout and accumulated 350, DD60’s is for foliage feeders, fall armyworms, and stinkbugs. Bolls set on the day of NAWF5 and after will be half as big as a lower boll. It will take twice the insect damage pay for an insecticide application.

Bollworm eggs and larvae were almost non-existent in cotton fields observed this week. Some plant bug nymphs and adults were observed in fields observed this week. Scattered beet armyworm hits were observed but survival from the hits was low and minimal foliage feeding was observed.

Northeast Counties - Mike Williams: The Bollworm moth flight is still going on in most of the NE Mississippi area with eggs being deposited down in the plant on bloom tags and square and boll bracts. Many of the hatching larvae are going directly into the end of the small bolls underneath the bloomtags. This makes them extremely hard to control, but they do come out of that area to move to another fruit, so insecticides are slow but generally effective. Budworm moth counts are increasing slightly, so treatment of non-Bt cotton with pyrethroids should be done with the idea that budworms will not be controlled effectively.

There are also some reports of clouded plant bugs in the northern counties of Mississippi and Tennessee border counties. These critters should be treated much like we do stink bugs, but they are usually seen in blooms. Stink bug counts may need to be done using the drop cloth. Remember when checking bolls to use the quarter-sized bolls for your survey.

Beet armyworms are still coming to pheromone traps in fairly high numbers in some areas and we still have reports of fall armyworm in grass crops. I’ve not seen any FAW in cotton, YET. Whole plant counts are in order. Check boll bracts for feeding by small worms.

Boll weevils are moving around now. This could be the last hoo-raa for Mr. Weevil, but rainshowers and maturing cotton has triggered them to move around. Hopefully, we will not see any weevil reproduction in Mississippi this year.

Trap reports for week ending July 17, 2002

County	Boll weevils	Bollworms	Budworms	BAW
County	no. per 33 traps	no. per trap/week	no. per trap/week	no. per trap/week
Coahoma		162.5	10.0	3.0
Tunica	0.0	132.5	46.4	9.0
Bolivar	1.0	98.3	27.7	7.7
Washington		0.0	0.0	0.0
Madison		8.0	4.0	4.0
Yazoo	0.0	33.0	10.5	24.5
Humphreys		177.0	29.5	128.5
Leflore		92.5	20.0	126.5
Carroll	0.0	41.0	96.0	27.0
Grenada	1.0	44.0	6.0	14.0

Cotton Insect Situation

Table 1: Small Plot Tarnished Plant Bug Efficacy Trial, Sunflower County, 2002

County