A new strategy of environmentally safe control of chestnut tortricid moths

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A new strategy of environmentally safe control of chestnut tortricid moths

Description

Abstract: Insect pest damage represents the mean restricting factor for the chestnut (Castaneasativa Mill.) fruit production in Italy and in Europe. Especially tortricid moth species areconstantly very noxious because their larvae feed on developing nuts, thus causing importantharvest losses. Although the early chestnut moth (Pammene fasciana L.) attack results only in anearly drop of fruits at the beginning of the development, more serious damages are produced bythe intermediate and the late chestnut moths, Cydia fagiglandana (Zell.) and C. splendana (Hb.),respectively. Larvae penetrate the nuts and develop into them, digging a tunnel and eating theendosperm. Usually damaged fruits fall during the summer, but in some cases they may completethe ripening and can be harvested as part of the crop. The chemical control of C. fagiglandanaand C. splendana is not advisable to preserve the naturalness of the final product and the safety ofthe chestnut grove. Moreover, the endophytic development of the larvae, the large size of thetrees and the characteristics of the Italian chestnut orchards make difficult and not economicallyadvantageous the use of pesticides.Previous studies conducted on the use of tortricid sex attractants showed a potential controlability on both species. On this basis a novel, low impact control method can be achieved bycombining the classical mating disruption approach to the use of a new kind of dispenser. Acanister housed in a plastic cabinet, called “puffer”, repeatedly sprays proper pheromone doseson a 12- or 24-hour schedule. Puffers, produced by Suterra®, are strategically located in thechestnut orchards, hung on tree branches at heights of 6-8m, in number of 2.5 per ha. Besides thelow impact for the environment, this approach shows many advantages since it is very easy toapply and, when optimised, also cheap. Therefore, a large scale trial was initiated to test theefficacy of this approach in three Italian regions: Trentino (north-eastern Italy), Tuscany (centralItaly) and Campania (southern Italy). In each region, 19 puffers were located in chestnut orchardareas of about 8ha. Traps (pagoda type), baited with specific pheromones, were installed atheights of 2-4m inside and outside the treated area to verify the effectiveness of the puffers. Foreach species, 3 traps were placed in the central part of the treated area and 3 traps in the untreatedplot and used as control. The traps were checked weekly, removing and counting adults. At theharvest time, fruit damage was also evaluated in treated and untreated areas.First data suggest that the “puffer approach” is quite easy to apply and feasible. Even if suchmethods need pluriannual trials to be evaluated, preliminary results are encouraging and suggestgood perspectives to obtain a complete biotechnical control of Cydia spp.

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