Known components of the female sex pheromone of Spodoptera littoralis (Boisd.), tetradecyl acetate (I), (Z)-9-tetradecenyl acetate (IIA), (Z,E>9,ll-tetradecadienyl acetate (III) and (Z,E)-9,12-tetradecadienyl acetate (IV), and related compounds dispensed from polyethylene vials were used to bait water traps and funnel traps in lucerne fields in Crete. In comparison with the catches of males in traps baited with the primary component (III) alone, catches were increased by the addition of 1-100% of I in relation to the amounts of III, decreased by the addition of 5% or more of IIA and decreased by the addition of more than 5% of IV. The diene III was more attractive than any of the other three geometric isomers, although combining the Z,Z isomer (V) or the E,E isomer (VI) with III increased catches while the addition of the E£ isomer (VII) decreased catches. The alcohols VIII and IX corresponding to the acetates III and IIA were not attractive but caused a marked reduction in trap catch when combined with III. The homologue of III (Z,£> ll-methyl-9,ll-tetradecadienyl acetate (X), was unattractive to males but increased trap catches when combined with III. 9-Tetradecynyl acetate (XI) exhibited neither attractant nor inhibitory activity, and similar results were obtained with ethyl cyclohexane carboxylate (XII) and 2-nonynal dimethyl acetal (XIII), compounds which have similar far-infrared spectra to that of diene III. The distributions of males landing on sticky board traps 70 cm in diameter baited with III or mixtures of III with I, IIA or IV showed that a greater percentage of the moths landed at the periphery of the traps baited with certain combinations of III with I and IV than on traps baited with III alone. Collection and analysis of the volatiles emitted by virgin females of different origins indicated that those from Crete produced I and III only, those from Israel produced I, III and IV, while those from Egypt produced I, III, IV and IIA and/or (E)-ll-tetradecenyl acetate (HB). The results are discussed in relation to previous work on S. littoralis and current theories on insect communication, and also in terms of their relevance to the practical field usage of pheromones in control of this pest. 418 D. G. CAMPION ET AL.

A large–scale mating disruption trial for the control of Pectinophora gossypiella (Saund.) was carried out in the Fayoum Province of Egypt during the 1981 cotton season. Two areas, each of 50 ha, were sprayed with a microencapsulated formulation of the sex pheromone (a 1:1 mixture of (Z, Z)- and (Z, E)-1, 11-hexadecadienyl acetate) as the sole means of controlling this pest. Five applications of 10 g a.i./ha were made during the season using fixed-wing aircraft. The pheromone treatments were compared with conventional insecticide spray treatments in two other 50-ha areas of cotton. From comparisons of treatments in terms of various plant damage criteria including the percentage of rosetted flowers, percentage boll infestation, gross yield of seed cotton and lint quality, it was concluded that the pheromone treatment was equal in effect to the insecticide sprays.

No abstract

A series of trials examining the feasibility of an attracticide technique for control of Spodoptera littoralis (Boisduval) are described. The technique combined the sex pheromone of 5. littoralis with the pyrethroid insecticide, A.-cyhalothrin, in 500 point-sources/ha at low rates of application of both components. It was envisaged that male moths would be attracted to contact the sources and subsequently suffer lethal or sub-lethal effects which would prevent mating. The pheromone was applied either as a sprayable microencapsulated (MC) formulation or in polyvinylchloride lures; emulsifiable concentrate and MC formulations of the insecticide were employed. Treatments were assessed by monitoring pheromone trap catches, mating of tethered females and, in one trial, numbers of egg-masses found in experimental areas. Mating levels and trap-catch in treatment plots were significantly reduced, compared to controls, for periods up to 5 and 24 nights after treatment, respectively. However despite a continuous period of mating suppression, achieved by repeated applications, no treatment-related reduction in eggmasses was observed. Two trials compared attracticide with mating-disruption treatments in which the insecticide was omitted. Similar levels of mating and trap-catch suppression were observed in the two treatments. It was concluded that the mating suppression observed in attracticide plots was due principally to disruption of chemical communication between the sexes, not to male mortality arising from contact with the insecticide sources. None of the attracticide treatments represented a viable control technique. Other practical and theoretical considerations arising from the results are discussed.

No abstract

The courtship of Spodoptera littoralis (Boisd.) was studied in closed cages containing an excess of the female sex pheromones (Z,E)-9,11-tetradecadienyl acetate (III) or (Z)-9-tetradecenyl acetate (IIA). High levels of III or IIA were obtained by using polyethylene vials loaded with 5, 1 or 0-1 mg of pheromone. Vials containing 10 or 1 ju.g released low levels of pheromone. Excess pheromone reduced mating; at high levels of III and IIA, only 15% and 42% of pairs, respectively, mated, compared with 92% of control pairs. Some 45% of courtships in control cages did not end in copulation, and in half of these the female rejected the male by giving a rapid flick of the wings. A detailed examination of unsuccessful courtships showed that an excess of III or IIA disrupted female courtship behaviour. At the higher levels of pheromone, no female wing-lifted to show acceptance of the male and only a few rejected the male by wingflicking. Significantly more females took to flight in cages containing III, whilst in cages with IIA females either took to flight or remained still. These changes in behaviour were still apparent in courtships where the female was calling and the male gave a full brush display. It is suggested that both III and IIA block olfactory reception of the male brush pheromone. An excess of either pheromone increased the proportion of male courtships of non-calling females. IIA had no other appreciable effect on male behaviour, but III also significantly reduced full brush displays during courtship, increased the period of flight preceding hovering and increased partial brush extension during flights that did not lead to courtship.

No abstract

Large-scale field trials conducted in three governorates in Egypt during the 1987 cotton season showed that two or three applications of pink boilworm pheromone (formulated as either microcapsules or hollow fibres) integrated with one or two applications of conventional insecticides gave as good a control of bollworms as did four or five applications of the insecticides alone. Estimated yields per feddan in two governorates, Fayoum and Dakahlia, averaged from 998 to 2164 kg in the pheromone-treated blocks compared to 1076 and 1628 kg in the insecticide-treated control blocks. While no significant differences in yields were detectable in the Fayoum, an increase of up to 17% in seed cotton weight was estimated in the pheromone-treated fields in Dakahlia. This increase in yield was attributed to enhanced hybrid vigour as a result of introducing beehives into the pheromonetreated fields during the early stages of flowering and fruit setting. The bees, in addition to cross-pollinating the cotton flowers, produced over 10 metric tonnes of honey. These excellent results were obtained in spite of a general increase in pink boilworm infestation throughout the governorate as deduced by a comparison of green boll infestation between 1986 and 1987. The results by a comparison of green boll infestation between 1986 and 1987. The results also underlined the importance of early season pheromone treatments, since the treatments at Dakahlia went on at an earlier stage of crop development than in either Kafr El Sheikh or Fayoum.