No abstract

Rice

The rice water weevil Lissorhoptrus oryzophilus (Coleoptera: Curculionidae: Brachycerinae) was detected in Northern Italy in 2004. As Italy is the major European rice producer, and the rice water weevil is considered to be one of the major pests of rice in the world, a multiyear study was carried out to determine the spread of the pest in Northern Italy, to evaluate its establishment potential and to improve the knowledge on its biology in this new habitat. The survey allowed the distribution of the insect in Italian rice areas to be evaluated and confirmed that L. oryzophilus behaves as a monovoltine parthenogenetic species in Northern Italy. Information about the phenology of the insect and its management are also provided.

Italy is the largest rice‐producing country in the European Union. In Italy, only japonica cultivars are listed in the Italian National Register. Almost all of the rice production is concentrated in the Po Valley, where the rice water weevil Lissorhoptrus oryzophilus Kuschel was first detected and settled. This study investigated the performance of this pest in terms of feeding, reproduction and plant injury on 10 rice cultivars chosen among the most widely grown in Italy. No‐choice experiments were conducted to evaluate the plant susceptibility to larval attack and to find out how cultivars can influence the adult leaf area consumption. The results gave evidence of different types of attack depending on the density of the insect (0.6 adults/plant vs. 0.9 adults/plant), the cultivar type and climatic conditions. Different cultivars with the same level of infestation gave different results in terms of productivity. Production was significantly affected by the larval presence in 4 of the 10 cultivars tested. A different population structure reflected a different damage severity. Statistically different values for total adult leaf area consumption were found according to adult female age and to the cultivar.