Woolly aphid (Eriosoma lanigerum Hausmann) (Hemiptera: Aphididae), was monitored over three growing seasons (1995)(1996)(1997)(1998) to assess its abundance and management under apple IPM programs at Bathurst on the Central Tablelands of NSW, Australia. Woolly aphid infestations were found to be extremely low in IPM programs utilising mating disruption and fenoxycarb for codling moth Cydia pomonella L. (Lepidoptera: Tortricidae) control. This was the direct result of increased numbers of natural enemies. No insecticides were applied for woolly aphid control. Under the IPM strategies tested the principal control agent was identified as European earwig (Forficula auricularia L.) (Dermaptera: Forficulidae). Earwigs in combination with Aphelinus mali (Haldeman) (Hymenoptera: Aphelinidae) reduced woolly aphid infestations below the action threshold set by commercial growers. However, A. mali together with other flying natural enemies, e.g., ladybirds, lacewings and hoverflies, did not provide commercially acceptable control of woolly aphid in the absence of earwigs. Under the conventional spray program, using the broad-spectrum insecticide azinphos-methyl for codling moth control, the level of woolly aphid infestation increased with each successive season and biological control was not established. When azinphos-methyl was withdrawn, natural enemies migrated in and provided control of woolly aphid within one season. This is the first study to show that the biological control of woolly aphid can be achieved in a commercially viable IPM program.
Female codling moth (Cydiupornonella) were mated either on the day of emergence or 2 or 4 d after emergence. Oviposition was checked daily and fertility ('70 egg hatch) of eggs laid 1-4 d and 5 + d after mating was determined from a sub-sample of females in each treatment. From these data, net reproduction rate (R,) was calculated. The effect of delayed mating of males was also determined. Mean fecundity, fertility and net reproduction rate of females mated 4 d after emergence were significantly lower than for females mated either on the day of emergence (day 0) or 2 d after emergence. There were no significant differences between the three treatments in terms of the proportion of females that mated or female longevity, although there was a trend towards increased longevity with increasing delays in mating. Mean longevity of unmated females was significantly greater than that of mated females. Oviposition pattern was similar in females regardless of when they were mated and in all cases maximum oviposition took place 2 d after mating. There was no effect on the fecundity of 2 d old females or on the fertility of their eggs when they were paired with either 2 or 6 d old males. The significance of these findings in relation to control of codling moth by mating disruption is discussed.
Adult diamondback moths (DBM), Plutella xylostella L. (Lepidoptera: Plutellidae), inoculated with the fungus Zoophthora radicans , were released within a large field cage containing DBM-infested potted broccoli plants. Larvae and pupae on exposed and caged control plants were examined on five occasions over the next 48 days for evidence of Z. radicans infection. Infected larvae were first detected on exposed plants 4 days after the initial release of adults, and after 48 days the infection level reached 79%. Aerially borne conidia were a factor in transmission of the fungus. Infection had no effect on possible losses of larval and adult cadavers due to scavengers in field crops. In a trial to measure the influence of infection on dispersal, twice as many non-infected as infected males were recaptured in pheromone traps, although the difference in cumulative catch only became significant 3 days after release of the males. In a separate experiment, when adult moths were inoculated with Beauveria bassiana conidia and released into the field cage, DBM larvae collected from 37 of 96 plants sampled 4 days later subsequently died from B. bassiana infection. The distribution of plants from which the infected larvae were collected was random, but the distribution of infected larvae was clustered within the cage. These findings suggest that the auto-dissemination of fungal pathogens may be a feasible strategy for DBM control, provided that epizootics can be established and maintained when DBM population densities are low.
Mating disruption of Cydia molesta (Busck) was attempted by treating, with pheromone, all orchards in a small but discrete peach-growing district in New South Wales for two successive years. In the final year of the trial, two former control orchards were also treated with pheromone. The efficacy of the treatment was examined by monitoring fruit and shoot damage, male captures in pheromone traps, captures of both sexes in feeding lures, mated status of wild females and numbers of immature stages in trap bands. It was concluded that mating disruption was a viable alternative to conventional insecticides.
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