Differential susceptibility of avocado cultivars to fruitspotting bugs, amblypelta spp. (Hemiptera: Coreidae)

Fruitspotting bugs are the major pests of avocados grown in Queensland, Australia. They feed on the fruit, which usually cracks, resulting in significant losses. Regular insecticide sprays are requi red to limit the damage. Thin-skinned cultivars have traditionally been considered to be more susceptible to the bugs because feeding damage is expressed on the thin skins as severe cracks and craters. The damage is thus more visible than it is in the thick-skinned cultivars, which often do not crack but form ‘blind stings’ that are easily overlooked. The bugs are difficult to detect in the trees and monitoring for their activity must be on the basis of damage to the fruit. Data obtained from a sprayed commercial orchard and from an unsprayed experimental block indicate that fruitspotting bugs prefer the thin-skinned cultivars of Fuerte and Wurtz to the thick-skinned cultivars of Hass and Sharwil. Pinkerton appears to be an exception for although it has a medium-thick skin, it was the first to be attacked, possibly because it set fruit earliest, and the damage inflicted was severe. In the sprayed commercial orchard, damage to Fuerte (1.9%) and Wurtz (4.3%) was significantly higher than that recorded on Hass (0.04%) and Sharwil (0.03%). In the unsprayed block, damage was 68.5% on Pinkerton, 73.6% on Fuerte and 18.9% on Hass. In orchards that consist of mixed plantings that include Fuerte, Wurtz or Pinkerton, these cultivars can be used as indicator trees for monitoring fruitspotting bug activity and also as decoy trees for targeted control.

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Bibliographic Details
Main Authors: Waite, G, Webb, K, Webb, M 130794
Format: Texto biblioteca
Language:spa
Published: 2003
Subjects:AVOCADO, BUGS, AGUACATE,
Online Access:http://www.avocadosource.com/wac5/Papers/WAC5_p515.pdf
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Description
Summary:Fruitspotting bugs are the major pests of avocados grown in Queensland, Australia. They feed on the fruit, which usually cracks, resulting in significant losses. Regular insecticide sprays are requi red to limit the damage. Thin-skinned cultivars have traditionally been considered to be more susceptible to the bugs because feeding damage is expressed on the thin skins as severe cracks and craters. The damage is thus more visible than it is in the thick-skinned cultivars, which often do not crack but form ‘blind stings’ that are easily overlooked. The bugs are difficult to detect in the trees and monitoring for their activity must be on the basis of damage to the fruit. Data obtained from a sprayed commercial orchard and from an unsprayed experimental block indicate that fruitspotting bugs prefer the thin-skinned cultivars of Fuerte and Wurtz to the thick-skinned cultivars of Hass and Sharwil. Pinkerton appears to be an exception for although it has a medium-thick skin, it was the first to be attacked, possibly because it set fruit earliest, and the damage inflicted was severe. In the sprayed commercial orchard, damage to Fuerte (1.9%) and Wurtz (4.3%) was significantly higher than that recorded on Hass (0.04%) and Sharwil (0.03%). In the unsprayed block, damage was 68.5% on Pinkerton, 73.6% on Fuerte and 18.9% on Hass. In orchards that consist of mixed plantings that include Fuerte, Wurtz or Pinkerton, these cultivars can be used as indicator trees for monitoring fruitspotting bug activity and also as decoy trees for targeted control.