Japonica cultivars' susceptibility to the rice water weevil Lissorhoptrus oryzophilus (Coleoptera: Curculionoidea: Brachyceridae)

Abstract

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.

A fungal endophyte helps plants to tolerate root herbivory through changes in gibberellin and jasmonate signaling

“…All plants infested with RWW adults showed numerous leaf feeding scars 2 d after infestation. This time period is within standard protocols for adult feeding bioassays (Stout et al, 2002;Lupi et al, 2013). The adults were then re-collected, the clip cage was removed, and a photograph of the injured leaf was recorded using a standardized focal distance.…”

Development of Oryzophagus oryzae (Costa Lima) in rice cultivars

“…Rice resistance to O. oryzae involves antixenosis, antibiosis or tolerance (Martins & Terres 1995), which is also used against infestations by the North American rice water weevil, Lissorhoptrus oryzophilus Kuschel (Coleoptera: Curculionidae) (N'Guessan et al 1994aand 1994b, Lupi et al 2013. Tolerance is the ability of plants to withstand damage by insect pests, maintaining the crop yield without affecting the behavior and development of phytophagous insects (Lara 1991).…”

“…It is worth noting that the adults weight has not been considered in pioneering studies on rice resistance to rice water weevil (Smith & Robinson 1982, Martins & Terres 1995 or in more recent studies (Lupi et al 2013, Stout et al 2013, Vyavhare et al 2016, Maisarah et al 2018. Thus, it is important to determine the applicability of this variable in the identification of antibiosis effects to O. oryzae, evaluating variables such as adult emergence rate, egg fecundity and viability, and chemical compounds present in rice plants.…”

Purification and Functional Characterization of a Soluble Trehalase in Lissorhoptrus oryzophilus (Coleoptera: Curculionidae)

“…The rice water weevil, Lissorhoptrus oryzophilus Kuschel (Coleoptera: Curculionidae), is the most harmful and widely distributed early-season pest of rice in the USA [ 20 ] and causes serious economic issues in wetland rice agriculture, resulting in losses of up to 25% in untreated fields [ 21 ]. Parthenogenetic female Lissorhoptrus oryzophilus ( L. oryzophilus ) have quickly invaded many rice-growing regions around the world [ 20 , 22 , 23 ]. In China, L. oryzophilus were first discovered in 1998; they have rapidly invaded 78% of the provinces and have become the foremost widespread invasive pest [ 24 ].…”