Search

The legume podborer, Maruca vitrata (syn. M. testulalis) (F.) (Lepidoptera: Pyralidae) is a pantropical pest of legume crops. Sex pheromone was collected by gland extraction or trapping of volatiles from virgin female moths originating in India, West Africa, or Taiwan. Analysis by GC-EAG and GC-MS confirmed previously published findings that (E,E)-10,12- hexadecadienal is the most abundant EAG-active component with 2–5% of (E,E)-10,12-hexadecadienol also present. At least one other EAG response was detected at retention times typical of monounsaturated hexadecenals or tetradecenyl acetates, but neither could be detected by GC-MS. Laboratory wind-tunnel bioassays and a field bioassay of blends of (E,E)-10,12-hexadecadienal with (E,E)-10,12-hexadecadienol and a range of monounsaturated hexadecenal and tetradecenyl acetate isomers indicated greatest attraction of males was to those including (E,E)-10,12-hexadecadienol and (E)-10-hexadecenal as minor components. In subsequent trapping experiments in cowpea fields in Benin, traps baited with a three-component blend of (E,E)-10,12-hexadecadienal and these two minor components in a 100:5:5 ratio caught significantly more males than traps baited with the major component alone, either two-component blend, or virgin female moths. Further blend optimization experiments did not produce a more attractive blend. No significant differences in catches were found between traps baited with polyethylene vials or rubber septa, or between lures containing 0.01 and 0.1 mg of synthetic pheromone. Significant numbers of female M. vitrata moths, up to 50% of total catches, were trapped with synthetic blends but not with virgin females. At present there is no clear explanation for this almost unprecedented finding, but the phenomenon may improve the predictive power of traps for population monitoring.

Trials to control the American bollworm, Helicoverpa armigera (Hübner) by the technique of mating disruption were carried out in the Pakistan Province of Punjab during the 1996 cotton season. A slow release PVC resin formulation, Selibate®HA, containing a 97:3 mixture of the major (9Z-hexadecenal) and minor (11Z-hexadecenal) components of the female sex pheromone of H. armigera was applied at a rate of 40 g active ingredient ha−1 during August 1996. The formulation was applied around the terminal portion of the cotton plant by hand using local labour at a rate of c. 250 pieces per hectare. The efficacy of the formulation was compared to conventional insecticide regimes to control H. armigera on four farmer practice fields situated at least 1 km to the north, south, east and west of the pheromone treated area. A high degree of trap catch shutdown (indicating mating suppression) was observed throughout the pheromone treated area during the whole of the season compared to non-pheromone treated farmer practice fields. Night observations confirmed that mating disruption occurred in the pheromone treated area as a smaller percentage of mated females were collected from this area compared to farmer practice fields. A majority of mated females collected from the pheromone treated area mated only once, whereas females in farmer practice fields had undergone multiple matings. A greater percentage of tethered female H. armigera moths retrieved from farmer practice fields had successfully mated compared to tethered females retrieved from the pheromone treated area. Release rate data of H. armigera pheromone from the formulation show that c. 70% was released during the two month trial period. However, the highly dispersive pre-oviposition flight behaviour of females meant that the area treated was not sufficient to eliminate the problem of gravid females migrating in from surrounding areas, and ovipositing therein. The implications of using the technique of mating disruption to control large strong flying insects like H. armigera are discussed.

Costa Rica is the fourth largest exporter of macadamia nuts, Macadamia integrifolia Maiden and Betche (Proteaceae), behind the USA, Australia and Kenya (Rosa & Kirby, 1994). Two thousand five-hundred hectares were planted in 1967 and a further 5000 ha in 1993, principally in the Province of Limon. The nuts are harvested by hand with the peak of production between July and October (Gonzales & Chacon, 1986). Attacks by an unidentified Lepidopterous nut borer began to be reported in macadamia orchards from the late 1980s with damage in isolated areas as high as 30%, although at the time, control with insecticides was not considered necessary (D.J. Chamberlain, unpubl.). Initially, the insect responsible for this damage was thought to have been Cryptophlebia leucotreta (Meyrick) (Lepidoptera: Tortricidae: Olethreutinae), a pest of macadamia prevalent in Malawi (La Croix et al., 1985). However, traps baited with lures containing blends of compounds attractive to both C. leucotreta (Persoons et al., 1977) and the related Cryptophlebia batrachopa (Meyrick) (Hall et al., 1984; La Croix et al., 1985) failed to catch any moths in the macadamia orchards. This paper describes the results of preliminary work undertaken to identify the pest species causing the damage and to develop a pheromone-baited trap for monitoring its population dynamics.

Comparisons of infestation and damage levels by the cotton bollworms, Pectinophora gossypiella (Saunders) (Lepidoptera: Gelechiidae), Earias vittella (Fabricius) and E. insulana (Boisduval) (Lepidoptera: Noctuidae) were made in cotton fields treated with pheromones + insecticide, insecticides only, and untreated control plots, in Pakistan during the 1991 cotton season. Early to mid season control of these three pests by mating disruption in the pheromone + insecticide treated plots meant that an average reduction of 3.5 applications of insecticides was achieved when compared with the insecticide only treated plots to control the cotton pest complex. Night observations showed that there were far fewer adult moths visible in the pheromone + insecticide treated plots than in insecticide only treated plots. Adults of both sexes were much less active and did not mate as frequently as adults in the insecticide only plots.

The False Pink Bollworm, Sathrobota (Pyroderces) simplex (Walsingham), was observed infesting open cotton bolls during the 1987/88 cotton growing season in the Punjab region of Pakistan. The larvae were, at that time, incorrectly identified as Pink Bollworm (PBW), Pectinophora gossypiella (Saunders). Their presence caused concern, as the area of infestation occurred in a field of cotton which had been treated with pheromone (gossyplure) to control infestation by P. gossypiella. Subsequently identification of the adults in the UK revealed that the majority of the infested bolls contained S. simplex and this was confirmed in trials conducted in the same area during the 1988/89 cotton growing season. This is the first record of S. simplex in Pakistan. The importance of S. simplex as a pest of cotton, and the evaluation of a pheromone formulation for monitoring adult populations, is described. Its significance as a pest of cotton is discussed.

( Z )-9-Totradecenyl nitrate and ( Z )-9-tridecenyl nitrate have been identified in volatiles from virgin female cotton leafperforator moths, Bucculatrix thurberiella , and shown to elicit electroantennogram responses from male moths. A 100:2 blend of the synthetic compounds is highly attractive to male moths in the field, and these compounds are proposed to be components of the female sex pheromone.

The legume podborer, Maruca vitrata (syn. M. testulalis) (F.) (Lepidoptera: Pyralidae) is a pantropical pest of legume crops. Sex pheromone was collected by gland extraction or trapping of volatiles from virgin female moths originating in India, West Africa, or Taiwan. Analysis by GC-EAG and GC-MS confirmed previously published findings that (E,E)-10,12-hexadecadienal is the most abundant EAG-active component with 2-5% of (E,E)-10,12-hexadecadienol also present. At least one other EAG response was detected at retention times typical of monounsaturated hexadecenals or tetradecenyl acetates, but neither could be detected by GC-MS. Laboratory wind-tunnel bioassays and a field bioassay of blends of (E,E)-10,12-hexadecadienal with (E,E )-10,12-hexadecadienol and a range of monounsaturated hexadecenal and tetradecenyl acetate isomers indicated greatest attraction of males was to those including (E,E)-10,12-hexadecadienol and (E)-10-hexadecenal as minor components. In subsequent trapping experiments in cowpea fields in Benin, traps baited with a three-component blend of (E,E)-10,12-hexadecadienal and these two minor components in a 100:5:5 ratio caught significantly more males than traps baited with the major component alone, either two-component blend, or virgin female moths. Further blend optimization experiments did not produce a more attractive blend. No significant differences in catches were found between traps baited with polyethylene vials or rubber septa, or between lures containing 0.01 and 0.1 mg of synthetic pheromone. Significant numbers of female M. vitrata moths, up to 50% of total catches, were trapped with synthetic blends but not with virgin females. At present there is no clear explanation for this almost unprecedented finding, but the phenomenon may improve the predictive power of traps for population monitoring.

PGBA, a plant growth facility developed for commercial space biotechnology research, successfully grew a total of 30 plants (6 species) for 10 days on board the Space Shuttle Endeavour (STS-77) and is scheduled for reflight on board MSL-1 (STS-83) for a 16 day flight. The PGBA life support systems provide atmospheric, thermal, and humidity control as well as lighting and nutrient supply in a 23.6 liter chamber. Atmosphere treatment includes ethylene and other hydrocarbon removal, CO2 replenishment, and O2 control. The normally closed system uses controlled CO2 replenishment from the crew cabin as required by the plants. Temperature is controlled (1 C) at user-specified setpoints between 20-32 C, using water-filled coolant loops, solid state Peltier thermoelectric devices, and liquid heat exchangers. The thermoelectric cooling systems were optimized for low power consumption and high cooling efficiencies. Relative humidity is maintained between 60-100% using a cooled porous metal plate to remove water vapor from the air stream without cooling the bulk air below the dew point. The lighting system utilizes three compact fluorescent bi-axial lights with variable lighting control and light intensity (PAR) between 220 and 330 micromol/sq m/s at a distance of 20 cm in spaceflight configuration (on orbit power limited to 230 Watt for entire payload). A ground, up to 550 micromol/sq m/s light intensity can be achieved with 330 Watt payload power consumption. Plant water and nutrient support is sustained via the 'Nutrient Pack' system including the passive or active 'Water Replenishable Nutrient Pack.' The root matrix material (soil or Agar) and nutrient formulation of each pack is prepared according to plant species and experimental requirements. These systems were designed by NASA Ames personnel. Data acquisition and control systems provide 32 channels of environmental data as well as digitized or analog video signals for downlink.

Ovipositor washings from virgin femaleEarias vittella (F.) (Lepidoptera: Noctuidae) moths were examined by gas chromatography (GC) linked to electroantennography (EAG). Six components were detected by the male moth. These were identified by comparison of their retention times with those of a range of synthetic standards on fused silica capillary GC columns as hexadecanal, (Z)-11-hexadecenal, (E,E)-10,12-hexadecadienal, octadecanal, (Z)-11-octadecenal, and (E,E)-10,12-hexadecadien-1-ol in 1∶2∶10∶2∶4∶1 ratio. Field testing in Pakistan showed that a 2∶10∶2 mixture of (Z)-11-hexadecenal, (E,E)-10,12-hexadecadienal, and (Z)-11-octadecenal was as attractive to maleE. vittella moths as the six-component mixture and equal in attractiveness to a virgin female moth. Omitting (Z)-11-hexadecenal or (Z)-11-octadecenal greatly reduced this attractiveness. It was found that synthetic lures must be protected from sunlight to prevent loss of attractiveness caused by isomerization of the conjugated diene aldehyde, and addition of (E,Z)-10,12-hexadecadienal, one of the products of isomerization, was shown to reduce attractiveness significantly. During this work, a 10∶1 mixture of (E,E)-10, 12-hexadecadienal and (Z)-11-hexadecenal was shown to be as attractive toE. insulana (Boisd.) male moths as a virgin female moth, and the attractiveness of this mixture was further increased by addition of (E,Z)-10,12-hexadecadienal.

Four species of Acridoidea were fed on wheat leaves with and without the condensed tannin, quebracho. In no case was it deleterious to survival and growth at levels below about 10% dry weight on the food. Similarly, consumption, digestibility, and utilization of food were unaffected at up to 10% dry weight. At higher concentrations, however, the consumption and the efficiency of conversion of digestion were reduced, although digestibility was little affected. The possible mechanisms for such tolerance are discussed, and contrast made with insects which are very sensitive to ingested condensed tannin.