Pink Bollworm1: Response of Native Males to Ratios of Z,Z- and Z,E
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1 Pink Bollworm : Response of Native Males to Ratios of Z ,Z - and Z ,E-Isomers of Gossyplure in Several Cotton Growing Areas of the World2,3 H. M. FLlN"f4, M. BALASUBRAMANlAN5, J. CAMPER06, G. R. STRICKLAND7, Z. AHMAD8, J. BARRAL9, S. BARBOSA10, AND A. F. KHAILII ABSTRACT J. Bean. Entomol. 72: 758-762 (1979) A standard test consisting of 7 ratios of the Z ,Z-, and Z ,E- isomers of gossyplure was conducted in several major cotton producing areas of the world to determine the pheromone preference of Pectinophora gossypiella (Saunders). Catches in traps baited with 50 or 60% of the Z ,Z- isomer in mixtures of Z ,Z-, and Z ,E- isomers were not significantly different in 5 of 7 areas (India, Australia, Pakistan, Argentina, and the U.S.). Catches by the 50% baits were significantly higher in Brazil, and catches with the 60% baits were significantly higher in Egypt. Therefore, baits with either 50 or 60% Z ,Z- isomer will be useful in surveyor control work throughout most of the area of distribution of pink bollworm. When the test was conducted several times during the season in Australia and Pakistan, catches indicated no shift from a statistically equal preference for baits containing 50 or 60% of the Z ,Z- isomer. Pexicopia sp., a genus related to Pectinophora, was captured primarily in traps containing 20% Z,Z- isomer and 80% Z,E- isomer at Kununurra, N.W. Australia. The genera may be isolated from each other by pheromonal preferences in those areas where the distributions overlap. The pink bollworm, Pectinophora gossypiella (Saun- were obtained by Boness (1975) in Spain. These are the ders), is an economic pest of cotton with world-wide only complete tests of ratios outside the United States of distribution. The moth was originally described in 1843 which we are aware. from specimens collected in India. It was reported as a Australian species of Pectinophora, including the pest of cotton in Africa in 1904 (Noble 1969) and has pink bollworm, appear to be reproductively isolated by been distributed to all major cotton-producing areas of variations of the ratios of Z ,Z-, to Z ,E- isomers of gos- the world. The pink bollworm entered Mexico in 1911 syplure (Rothschild 1975). The Z,E- isomer of gossy- in seed imported from Egypt and entered the U.S. in plure was identified by Vick et al. (1974) as the primary 1917 in Texas. pheromone of the Angoumois grain moth, Sitotroga cer- Female pink bollworms produce a sex pheromone that ealella (Olivier). Widely distributed "pheromonal phen- is attractive to male moths (Ouye and Butt 1962). It was otypes" (Klun et al. 1975) or sibling species (Carde et identified as a 1:1 mixture of the Z and E geometrical al. 1978) of the European com borer use various blends isomers of 7, II-hexadecadien-l-o 1 acetate by Hummel of 2 component pheromone for communication. Among et al. (1973) who proposed the name gossyplure. Flint et these tortricine moths attraction specificity appears to be al. (1977) reported that a mixture containing 60% of the a primary mechanism for species partitioning (Minks et Z ,Z- isomer and 40% of the Z ,E- isomer was more at- al. 1973, Carde et al. 1977). Thus, considerable diver- tractive early in the season than the 1:1 ratio, and this gence can occur in pheromone communication systems finding was confirmed in studies of the seasonal re- among closely related species, and there is divergence sponse of native and released laboratory-reared moths even within species that have been geographically or (Flint et al. 1978b). otherwise isolated. These studies indicate the necessity Tests in Australia (Rothschild 1975)indicated that the for considering pheromonal variability in programs in pink bollworm responded better to the 1:1 ratio than to which pheromones are to be used for either surveyor a 10:1 ratio; however, intermediate ratios were not control of widely distributed pests. tested. Marks (1976) reported that the response of the In the case of the pink bollworm, recent development pink bollworm to a wide range of ratios of Z,Z-, and of control techniques such as confusion (Gaston et al. Z ,E- isomers in Malawi showed preference for mixtures 1977) and trapping (Huber et al. 1979) plus the need to containing 55-60% of the Z ,Z- isomer. Similar results survey and monitor populations have made it necessary to determine pheromonal response of pink bollworm I Lepidoptera: Gelechiidae. I In cooperation with the Ariz. Agric. Exp. StD. Tucson. Received for publi- males in cotton producing areas outside of the U.S. We cation May 7. 1979. • Mention of a propielory product does not coostiOlte endorsement by USDA. report here the results of such determinations in several • Western COllon Research Laboratory. Agric. Res. SEA. Phoenix. AZ 85040 . areas of the world. • Dept. of AgriculD1ral Entomolo8Y. AgriculD1ral College and Research Iosti- Olle. Coimbatorc 641 003. India. • Jefe Seccion de Enlomologia. UNDPIFAO. Av. de Circunvalacion. Casilla Materials and Methods 1281. Santa Cruz de la Siena. Bolivia. , Dept. of Agric .• 0.0. Box 19. KununUlT8, Weslern Australia 6143. General Methods I COlton Research Institule. Ministry of Food. Agric., and Undet Developed Areas. Multan, Pakistan. A standardized trap test for the pink bollworm was I I.N.T.A. Estacion Experimental, Casilla de Correa No. 164,3100 Pcia. Ro- que Saenz Pcna, Chaco. Argentina. conducted in several parts of the world. The standard 10 Centro Nacional de Pesquisa do A1godao. Divisao de Improtacao da EM· test consisted of 20 traps of each of 7 mixtures of the BRAPA, Super Cenler Venancia 2.000·8. ander, 70.000 - Brasilia· Of Brasil. II Sakha Agric. Res. Station. Kafr EI Sbeikh, Egypt. Z ,Z-, and Z ,E- isomers of gossyplure (20, 30, 40, 50, 758 October 1979 FLINT ET AL.: PINK BOLLWORM RESPONSE TO GOSSYPLURE 759 60, 70, and 80% of the Z ,Z- isomer). All test materials later in the season in the same area. Moths from traps except the stakes for hanging the traps were prepared in containing 20, 50, or 80%Z ,Z- isomer were returned to Phoenix and immediately air mailed to the cooperators the U.S. for identification. for placement in the field. Test traps were usually ex- In India, the standard test was conducted in commer- posed for 2 weeks or until a catch of ca. 50 moths/trap cial short staple cotton at Coimbatore on Nov. 21, 1976. was obtained in the traps with the greatest catches. The The traps were checked weekly for a period of 4 weeks. arrangment of the traps in fields was determined by the The temperatures in the test area were very cool during cooperators, but specifications required a minimum of December, and moth populations declined sharply as the 30 m between traps and that a randomized block design growing season was terminated. Moths from traps con- be used in placement of the 7 treatments. taining 50% Z,Z- isomer were returned to the U.S. for The traps used at all locations were Delta traps (Te- identification. tron Inc., Newark, NJ) originally designed for survey of In Brazil, the standard test was conducted July 12-19, the gypsy moth, Lymantria dispar (L.). Baits were made 1978, mid-season in the test area. During this season from rubber septa (no. IF-66F red rubber septa, the temperatures never went below 20°C, and rains were West Co., Phoenixville, PA) treated with lOOO~gof frequent. The cotton was cultivated perennial variety lure dispensed in 50~liters of methylene chloride (dich- Gossypieum hirsutum L. var. marie-galante (Watts) J. loromethane) (Flint et al. 1974, Maitlen et al. 1976). B. Hutch in its 2nd year of growth. The plants had The lure and solvent were placed in the up-turned cup of squares, flowers, and bolls. the septa and allowed to penetrate the rubber, usually In Pakistan, during the 1977 season, 5 traps for each within 5 min. Baits prepared in this manner are effective ratio were placed in a 2-ha field planted with Gossypium in the field for several months (Flint et al. 1978a). The hirsutum var. 149F. The traps were checked weekly and Z,Z-, and Z,E- isomers of gossyplure used in the tests replaced each month June-October 1977. When the were obtained in a single lot in 1976 from Farchan traps were set out June 8, the cotton was the earliest Chemical Co., Willoughby, OH. These isomers were available in an area where cotton farming is intensive, bioassayed in field tests with isomers of known purity and application of insecticides had begun (for control of (greater than 97% purity of isomers) obtained from R. thrips). Five traps/ratio were replaced each month. The T. Staten (Animal and Plant Health Inspection Services, field was treated with insecticides at irregular intervals Phoenix, AZ) and trap catches were not significantly during the test period. different. These isomers also were used in other studies In 1978, the standard ratio test was conducted in fields conducted during 1976-78 (Flint et al. 1977, 1978a, b, of B. 557 variety. The test was begun July 13 and ter- Smith et al. 1978). minated Aug. 17. Traps were checked and cleaned Results were analyzed by analysis of variance (AOY) weekly. The same traps and baits were used throughout using a program that provided for missing data where the test period. necessary (missing data were infrequent). When a sig- In Australia, the standard test was conducted at Ku- nificant AOY was obtained, a Duncan's multiple range nunurra in the Ord Irrigation District, Western Australia, test was used to partition the means into significant during the 1977 season.