Spirotetramat is toxic to leafrollers on kiwifruit

Spirotetramat is an ambimobile selective insecticide used widely in the horticulture industry for controlling a broad range of sucking pests in perennial and annual crops It has become the standard chemical for the control of armoured scale insects in kiwifruit During an experiment to test the effects of spirotetramat (formulated as Movento 100SC) on phytohormone levels it unexpectedly caused high levels of mortality to neonate brownheaded leafroller (Ctenopseustis obliquana) larvae (96 of treated plants with dead larvae compared with 9 in unsprayed controls) exposed one day after spraying to runoff on small potted A deliciosa Hayward plants Repeating the experiment with different plants and third instar larvae resulted in 98 treatment mortality compared with 29 on untreated controls A third experiment using neonate larvae applied to the same plants as the second experiment 10 days after the spray application resulted in 76 treatment mortality compared with 20 on control plants Spirotetramat can only be used preflowering and leafroller control sprays are applied principally during the first 6 weeks after fruit set However the potential contribution of spirotetramat to leafroller control on kiwifruit should be investigated further

A comparison of lepidopteran damage to Hort16A and Hayward kiwifruit

The timing and incidence of lepidopteran damage to two kiwifruit cultivars Hort16A and Hayward were compared by monitoring tagged fruit bunches on unsprayed vines over two seasons In both seasons the percentage of fruit with caterpillar damage increased rapidly during the 8 weeks immediately after fruit set No new damage was found on Hort16A fruit after this time but Hayward fruit continued to be damaged from February until May Only 74 (both seasons) of Hort16A fruit incurred severe damage (nonexport) compared with 11 7 (1997) or 184 (1998) of Hayward fruit Damage to Hort16A fruit was generally to the sepal area or side of fruit whereas the side of fruit or stamen end were the most common feeding sites on Hayward Ctenopseustis obliquana and Stathmopoda spp caterpillars were the predominant species found on Hort16A fruit while C obliquana and Cnephasia jactatana were the most common species found on Hayward fruit

Techniques for detecting Actinidia resistance to leafrollers

Hayward and Hort16A kiwifruit are susceptible to attack by the brownheaded leafroller (BHLR) Ctenopseustis obliquana but the incidence and severity of damage to Hayward can be twice that of Hort16A Three bioassay techniques were tested for their ability to detect differences in the relative susceptibility of the two kiwifruit cultivars to BHLR larvae No differences were detected when larvae were reared on artificial diets containing Hayward or Hort16A plant material Significantly more larvae survived when reared on Hayward versus Hort16A leaf discs Caging larvae onto leaves and fruit resulted in significantly more damage to Hayward compared with Hort16A Measuring larval survival after 21 days on leaf discs or the incidence and severity of damage caused by larvae caged on leaves or fruit are both potential techniques for screening Actinidia plant material for resistance to leafrollers

Species composition and abundance of leafrollers in a Canterbury pine plantation

Several leafroller species (Tortricidae) are known to occasionally cause considerable defoliation in Pinus radiata plantation forests We conducted pheromone trapping for five indigenous species Ctenopseustis herana Ctenopseustis obliquana Planotortrix excessana Planotortrix notophaea and Planotortrix octo and the exotic Epiphyas postvittana to determine their abundance in 20 P radiata stands in Eyrewell Forest North Canterbury Trapping from December 2001 to February 2002 indicated that E postvittana and C obliquana were very abundant (with mean catches of 077 and 044 moths/trap/day respectively) while the other species were rarely caught Results for the native leafrollers differ considerably from those reported from other plantation forests and other habitats in Canterbury such as apple orchards where P octo and C herana are generally more common

Larval feeding behaviour and toxicity of Bacillus thuringiensis against Ctenopseustis obliquana on avocados

Ctenopseustis obliquana is a serious pest of avocado in New Zealand Laboratory experiments to gain a greater understanding of the interaction between larval feeding behaviour and environmental degradation of Bacillus thuringiensis (Bt) residues were carried out Larval C obliquana were found to feed equally during light and dark periods and the application of Bt sprays in the evening did not consistently result in higher mortality than sprays applied in the morning First instar larvae were more susceptible to Bt sprays than third instar larvae However when first instar larvae were provided with leaf discs that had been sprayed with Bt seven days previously mortality was equivalent to that of larvae feeding on unsprayed leaves Mortality of first and third instar larvae provided with Bttreated leaf discs collected from within the shade of the avocado tree canopy (zero and one day after spraying) was significantly greater than that of larvae provided with Bttreated leaf discs collected from the outer perimeter of the canopy Results indicated that even very short exposure to sunlight (ie 3060 minutes) was sufficient to cause a significant reduction in the toxicity of Btsprayed leaves to C obliquana larvae

Waterblasting avocados to remove leafroller eggs

The potential for highpressure waterblasting to remove leafroller egg rafts from the surface of Hass avocados after harvest was investigated Water pressures from 400 to 1000 psi were tested Pressures of 800 and 1000 psi removed 96999 of greenheaded leafroller (Planotortrix octo) egg rafts in two consecutive seasons Equal numbers of brownheaded leafroller (Ctenopseustis obliquana) egg rafts were also removed at pressures of 800 psi Natural infestations of thrips mites and leafroller larvae were completely removed at pressures from 400 to 1000 psi but armoured scale pests remained on the fruit Waterblasted fruit met current industry quality standards