Pest Management Short Course: The Pest Management Short Course is scheduled for March 19 & 20 of 2003. This year’s program has been expanded to include crops other than cotton. The purpose of this training is to provide detailed information on the biology, management, and control of the insects, diseases, and weeds that affect Mississippi crops. The training is approved for consultant license renewal, Research and Demonstration license renewal, and CCA Training Credits. Call the Department of Entomology and Plant Pathology (662-325-2085) for information.

                                        Pest Management Short Course
                                        Begins: 9:30 AM, March 19, 2003 (registration begins at 8:30 AM, $10.00)
                                        Ends: 12:00 noon, March 20, 2003
                                        Location: Bost Building, Theater, Mississippi State University

Program Outline:      8:30 AM – 9:30 AM, March 19 Registration
                               9:30 AM – 2:00 PM, March 19 Weed Science Session
                               2:00 – 5:00 PM, March 19 Plant Pathology Session
                               8:00 AM – 12:00, March 20 Entomology Session

Change for 2003 Newsletter: This year the scope of the newsletter will be expanded to include other row crops. Although much of the information in the newsletter will still focus on cotton, articles on insect pests of corn, sorghum, soybeans, and rice will also be included.

Subscription Renewal Cards: If you would like to receive the Mississippi Row Crop Insect Situation Newsletter in 2003, please complete and return the enclosed subscription renewal card. There is no charge for receiving this newsletter. Also, if you know someone who would like to receive the newsletter, they can have their name added to the mailing list by calling 662-325-2085, or by sending their name and address to: Row Crop Insect Situation Newsletter, Box 9775, Mississippi State, MS 39762-9775.

Review of 2002 Cotton Entomology Season: Each year each cotton-producing state prepares a summary of the cotton insect season for inclusion in the Proceedings of the Beltwide Cotton Conference. These summaries provide a historical record of cotton insect pressure. A copy of the summary for last year in Mississippi is enclosed. One can also access summaries for past years by going to the MSUCARES Cotton Insect Web Site (www.msucares.com/insects/cotton) and selecting "Annual Summaries of Mississippi’s Cotton Insect Season" from the menu at the bottom of the page.

Review of the 2002 Cotton Insect Season In Mississippi

Blake Layton
Extension Cotton Entomology Specialist

Mississippi: Mississippi cotton producers planted approximately 1.18 million acres of cotton in 2002, which was a substantial decrease from the 1.62 million acres planted in 2001. Approximately 81% of the crop was planted to transgenic Bt varieties, with Paymaster 1218 BG/RR, Deltapine 451 BR, and Stoneville 4892 BR being the dominant varieties. Collectively these three Bt varieties were planted on 51% of Mississippi’s cotton acreage.

Active Boll Weevil Eradication Programs (BWEP) were underway in all areas of the state in 2002. Although boll weevil numbers were very low through out the state, no area of the state has yet achieved eradication. The Hill Region, which contained approximately 415,000 acres, was in its sixth year of BWEP. The South Delta Region, consisting of approximately 175,000 acres, was in its fifth year, while the approximately 568,000 acres in the North Delta was in the fourth year of BWEP. This was the final year for the BWEP in the South Delta Region, but growers in this region voted to enter a ten-year Boll Weevil Eradication Maintenance Program in 2003. Growers in the Hill Region of the state voted in a similar maintenance program in 2001, and growers in the North Delta are scheduled to vote on a maintenance program in 2003. The annual assessment fee for these maintenance programs, which is not to exceed $12.00 per acre, will be used to complete the eradication effort, service any residual debt from the original program, and to run an effective eradication maintenance program.

Heavy, prolonged rainfall during late August and early September of 2001 prevented effective late summer and early diapause treatments, and the suspension of aerial application following the September 11 terrorist attacks further reduced the effectiveness of the 2001 BWEP diapause program. This less than desirable diapause program was followed by a mild winter, which allowed good survival of overwintering boll weevils. As a result, during the early part of the 2002 season, statewide weekly boll weevil trap captures were actually somewhat higher than they had been the previous year, even though considerably fewer acres of cotton were being trapped, and it was not until the first week of August that 2002 weekly captures dropped below those for 2001. Still, the total number of boll weevils being captured statewide during May, June, and July, was quite low, ranging from a high of 5386 in the second week of June to a low of 916 during the third week of July. Although weekly statewide boll weevil trap captures increased during late August and September as weevils began to enter diapause, these numbers were somewhat lower that those for corresponding weeks in the previous year, indicating that the BWEP had regained the ground it lost as a result of the disappointing 2001 diapause season and ended the season showing some progress toward the goal of completely eradicating the boll weevil from Mississippi. The total number of boll weevils captured statewide during 2002 was 191,570, compared to 346,420 in 2001, but the average number of ULV malathion sprays applied per acre was 1.5, which was actually higher than the 1.2 sprays applied in 2001.

Late April and early May of 2002 were dry, and unusually warm, and 70% of the crop was planted by May 12. Unfortunately, the following two weeks of May were unusually cool, with night temperatures dropping into the low 40s in some areas of the state. These low temperatures slowed seedling development, resulting in increased incidence of seedling disease and prolonging the window of susceptibility to thrips. Although thrips numbers were not unusually high, the number of foliar treatments applied to control thrips was higher than normal because of this prolonged period of susceptibility. Because of budget concerns, there also appeared to be an increase in the percentage of acreage that was not treated with an in-furrow insecticide, and this also contributed to an increased need for foliar thrips treatments.

Availability of transgenic herbicide tolerant varieties has fostered a large increase in no-till production, especially in the Hill Region of the state where the portion of fields planted no-till exceeds 80% in some counties. This increase in no-till acreage has resulted in an increase in unconventional pest problems, especially in seedling cotton. This year many no-till fields experienced particularly high populations of snails. Although they do not appear to cause any significant feeding injury, these snails often congregate on seedling cotton plants in extremely high numbers, causing the plants to lodge under their weight. This phenomenon has been sporadically observed in no-till cotton for many years, but was more widespread this year because of the increase in no-till acreage. Although they were not causing any visible damage, these snails, which were identified as members of the genus Succinea, generated concern among growers because they were so numerous. The snails rest on the leaves and stems of the seedling cotton plants, causing them to droop and lodge. A number of fields were treated with foliar insecticide sprays in an unsuccessful attempt to obtain control.

Heavy, early spider mite infestations were another phenomenon that was observed in many no-till fields in the South Delta region of the state. Although this situation was not wide spread, there were a number of fields that required treatment to control infestations of spider mites on seedling cotton. In one case these mites were identified as Carmine mites, Tetranychus cinnararinus. Apparently the mites moved to the cotton seedlings from in-field infestations of weeds that were killed by burn-down herbicide treatments. It is likely that these mite infestations were exacerbated by applications of pyrethroid insecticides that are routinely applied at-planting in no-till fields to control cutworms. Fortunately however, spider mite populations were not particularly heavy during the remainder of the season.

Early season tarnished plant bug populations were highly variable across the state in 2002. As usual, plant bug numbers were much heavier in the Delta, which averaged approximately 3.5 foliar plant bug sprays, than in the Hills, which averaged approximately 1.1 treatments for plant bugs. Although, plant bug populations remained uncommonly low in many areas of the Delta through mid-July, the northern Delta, which experienced unusually heavy spring rainfall, experienced heavy early season plant bug pressure. As in recent past years, plant bug numbers increased through much of the Delta during mid and late-season, resulting in a considerable amount of treatment for plant bugs during the latter half of the growing season. Successful control of these heavy, late-season infestations required at least two successive applications of an effective plant bug insecticide.

Plant bugs in the Delta exhibit high levels of resistance to pyrethroid insecticides, and acephate and dicrotophos continued to be the most effective treatments for plant bugs. Although thiamethoxam (Centric) was used in many Delta fields, many of these early applications were made prophylactically when plant bug populations were low or absent, making it difficult to evaluate effectiveness. However, in small plot trials the performance of thiamethoxam was similar to that of acephate and dicrotophos. As in past years, Bt-cotton required significantly more tarnished plant bug treatments than non-Bt, because of the lower number of treatments required to control caterpillar pests and the corresponding reduction in coincidental control.

Cotton aphid populations were relatively low in 2002 with few fields requiring treatment. As in past years, fields that received multiple applications of ULV malathion as part of the BWEP were especially prone to aphid infestations. The new neonicotinoid products, Thiamethoxam (Centric) and acetamiprid (Intruder), provided excellent control of aphids in fields that required treatment, as did carbofuran (Furadan), which was again available for use under a Section 18 Emergency Exemption.

Following the mild winter it was anticipated that stink bugs might be more common than in past years. However, although stink bug infestations were heavier than usual in soybeans, treatable infestations did not occur in cotton to the degree expected. Still, there were a few fields that were treated specifically to control stink bugs, a situation that rarely occurred in the years before BWEP and wide spread use of Bt-cotton

With approximately 81% of the crop planted to Bt varieties, tobacco budworm infestations were relatively uncommon, but some non-Bt fields did require treatment for tobacco budworms. Statewide corn acreage was up approximately 140,000 acres, with much of this increase being concentrated in the Delta region. As a result, bollworm pressure was relatively heavy, particularly in the Delta where Bt fields received an average of 2.0 foliar treatments to control caterpillar pests and non-Bt fields received 5.3 caterpillar treatments. Bollworm/budworm pressure was much lower in the Hill region where Bt fields received approximately 0.7 caterpillar sprays and non-Bt fields received 2.1 caterpillar sprays.

It is especially noteworthy that there were many non-Bt fields in the Hills, including many large fields that were not being grown as a refuge for Bt-cotton, which required no treatments for caterpillar pests and sustained very little insect damage. The lack of insect pressure in these fields is attributed to three major factors. Most important is the boll weevil eradication effort, which by eliminating the need for boll weevil treatments favors season-long retention of beneficial insect populations. Also, many Hill fields are currently planted no-till, and no-till cotton fosters in-field establishment of fire ants, which are extremely effective predators on heliothine eggs, larvae, and pupae. In addition, the large percentage of acreage planted to Bt varieties serves to dilute the overall tobacco budworm population, resulting in lower numbers of tobacco budworm moths and lower tobacco budworm pressure in non-Bt fields.

Beet armyworms were only a sporadic problem in 2002, with most of the fields that required treatment for beet armyworms being located in the South Delta. Fall armyworm infestations were more widely spread across the state, but in most cases, fall armyworms were not detected until very late in the season. Few treatments were applied specifically to control fall armyworms, but it was not uncommon to encounter low level infestations of fall armyworms in fields during late season. In most cases these late season fall armyworm infestations appeared to be sub-economic.

Loopers were somewhat more common than usual and there were a number of fields, especially later-maturing fields that either received a treatment specifically to control loopers or received a treatment to control a mixed population of loopers and bollworms.

Damaging infestations of whiteflies were uncommon, and very few fields required treatment for whiteflies.

By early September it was evident that statewide yield potential was much better than average and early harvest reports indicated excellent yields. During late September, Hurricane Isadore resulted in extremely heavy rainfall across the state, causing significant crop loss and interrupting harvest for many days. Unfortunately, this event was followed by a prolonged period of unseasonably frequent rainfall that that lasted throughout October and November and further interfered with timely harvest. As of the first week of November the crop was only 60% harvested, which was well behind the 5-year average of 94% harvested by this time. This delay in harvest resulted in additional weather related loss, both in yield and quality, making this the second consecutive year that Mississippi growers have made an excellent cotton crop, only to see it severely diminished by excessive late season rainfall. Estimated statewide yield for 2002 is approximately 826 lbs of lint (January, 2003 NASS Estimate), which despite the adverse harvest season, is well above the previous five-year average of 741 lbs.

In summary, overall insect pressure was relatively low in the Hill region of the state, but was much heavier in the Delta, which experienced relatively heavy bollworm pressure, as well as late season plant bug infestations. Yield potential of the crop was much better than average going into harvest, but was diminished in both yield and quality by excessive, prolonged rainfall during the harvest season. Mississippi continued to make progress in its effort to eradicate the boll weevil, but low numbers of this pest are still present in all eradication regions of the state. Statewide, insect induced yield losses were estimated at 6.8%, and the estimated average costs of insect control were $94/acre. Total per acre costs of insect control were estimated to be substantially higher in the Delta, $109/acre, than in the Hills where estimated insect control costs were only $63/acre.

__________________________
Blake Layton
Extension Entomologist

Area Specialists:   Dr. Gordon Andrews
                            Dr. Mike Williams
                            Dr. Don Parker