The efficiency of Monte-Carlo procedures to test some hypotheses about the spatial patterns of larvae and damages of Lobesia botrana was studied. Two hypotheses were tested to detect spatial heterogeneity and spatial dependence. The most practical implication is to provide an efficient sampling scheme. The study of the relationship between spatial patterns and grape availability was required to explain scales of spatial heterogeneity and population dynamics studies were needed to relate it to oviposition behavior. It was tested through a third hypothesis. We adapted Monte-Carlo simulation procedures for the analysis of exhaustive count data obtained from regular grids delimited within each of two vineyards. Statistical analyses were based on count permutations and on count redistributions according to the hypotheses which were tested. Indices of aggregation and autocorrelation statistics were used. The hypotheses that we tested at different scales were random distribution of the infestations (HR), independence of vine stock (or groups of k vine stocks) infestation (HI) and independence between vine stock infestation and grape availability (HG). Monte-Carlo tests revealed the same spatial patterns for larvae and damages. We detected different spatial patterns. The implications for sampling were that sample unit could be an individual stock and that sampling along a row could not be used to estimate population density in the vineyard. Results showed that infestation of a given stock depended on grape availability on this stock and on neighboring vine stocks., Isabelle Badenhausser, Patrice Lecharpentier, Lionel Delbac, Pascale Pracros, and Lit
Ex ovo larvae of Lobesia botrana were reared on flowers and fruits of known and potential host plants. both in the laboratory and in the field. Development rates indicated a wide range of host suitability. In the laboratory, larvae of L. botrana had higher survivorship and shorter development time when reared on Vitis vinifera, Prunus persica (nectarina), Taraxacum officinale or Prunus domestica than when reared on Malus pumila, Pyrus amygdaliformis, Prunus armeniaca, Prunus cerasus, Syringa vulgaris or Papaver rhoeas. Similar results were obtained in the field. In no-choice tests in the laboratory, more eggs were laid on fruits than on flowers. Fruits of Prunus domestica, Vitis vinifera and Prunus persica (nectarina) were most preferred as oviposition sites.
Plant volatiles can synergize the response to moth pheromone. Synthetic pheromone analogs, in turn, have the opposite effect in reducing pheromone attractiveness. To determine how these two types of stimuli interact and influence male moth behaviour, we performed wind tunnel experiments on the grapevine moth, Lobesia botrana. We noticed that a blend of host plant volatiles [(E)-β-caryophyllene, 1-hexanol, (Z)-3-hexenyl acetate and 1-octen-3-ol in a 100:20:10:5 ratio] significantly increased the response of males to an optimized blend of sex pheromone [(7E,9Z)-dodeca-7,9-dienyl acetate (E7,Z9-12:Ac), (7E,9Z)- dodeca-7,9-dienol (E7,Z9-12:OH) and (Z)-9-dodecenyl acetate (Z9-12:Ac)] in a 100:10:2 ratio. However, the response of males to the natural attractant was significantly reduced by two analogs [(9E,11Z)-tetradeca-9,11-dien-2-one (MK 2) and [(9E,11Z)-1,1,1-trifluoro-tetradeca-9,11-dien-2-one (TFMK 3)], of the major component of the sex pheromone of the insect (E7,Z9-12:Ac). When both stimuli were tested on males at pheromone:analog:plant volatile blend 1:100:1000 ratio, the plant blend offset the inhibitory effect induced by TFMK 3 but not that of MK 2. Our results show for the first time that under laboratory conditions plant volatiles can prevent inhibition by a pheromone analog., Albert Sans, Miguel Morán, Magí Riba, Ángel Guerrero, Jaume Roig, César Gemeno., and Obsahuje bibliografii
Studies were conducted to investigate the distribution of larvae of the European vine moth, Lobesia botrana (Denis & Schiffermüller) (Lepidoptera: Tortricidae), a key vineyard pest of grape cultivars. The data collected were larval densities of the second and third generation of L. botrana on half-vine and entire plants of wine and table cultivars in 2003-2004. No insecticide treatments were applied to plants during the 2-year study. The distribution of L. botrana larvae can be described by a negative binomial. This reveals that the insect aggregates. A common value for the k parameter of the negative binomial distribution of kc = 0.6042, was obtained, using maximum likelihood estimation, and the advantages and cases of use of a common k are discussed. The k-1Sinh-1(ksqrt{x+1/2}) and k-1Sinh-1(ksqrt{x+3/8}) proved to be the best transformations for L. botrana larval counts. An entire vine is recommended as the sampling unit for research purposes, whereas a half-vine, which is suitable for grape vine cultivation in northern Greece, is recommended for practical purposes. We used these findings to develop a fixed precision sequential sampling plan and a sequential sampling program for classifying the pest status of L. botrana larvae.