Search

Aim of the study was to investigate the performance of the new insecticide "spirotetramat" as an alternative solution of "abamectin" for the control of Cacopsylla pyri L. (Hemiptera: Psyllidae) in the context of an IPM program in European pear, Pyrus communis L.. Laboratory bioassays for the estimation of LC50 and LC90 of both insecticides were performed using four populations collected in Emilia-Romagna (Italy) orchards where different pest management strategies were used (organic, integrated, and conventional). The same populations were also analyzed for the main insecticide detoxifying activities in nymphs by spectrofluorimetric in vitro assays. The performance of the two insecticides was also tested on field on one population under integrated pest management conditions. The laboratory experiments showed that the LC90 of spirotetramat were lower than the highest field concentration allowed in Europe (172.80 mg AI liter(-1)) giving reassurance about the efficacy of the product. Concerning the abamectin, the laboratory bioassays did not show strong indications of resistance development of C. pyri populations of Emilia-Romagna. A similarity in enzyme detoxifying activity was observed in both insecticides indicating a general absence of a significant insecticide resistance. The field trial showed a high efficacy (90 %) of spirotetramat on C. pyri already after 15 d from application, and it was significantly higher from abamectin. Overall, spirotetramat is one more choice for C. pyri control, as well as abamectin in order to minimize the risks of occurrence of insecticide resistance.

Cyantraniliprole is a novel insecticide for control of multiple chewing and sucking insect pest species including the sweetpotato whitefly Bemisia tabaci (Gennadius), which is one of the most important polyphagous pests in tropical, subtropical, and Mediterranean regions. This study aims to evaluate the effects of cyantraniliprole on the probing behavior of B. tabaci on tomato. Electrical penetration graph data indicated that on plants treated with cyantraniliprole (foliar application), adult whiteflies of the genetic variant Q2 were not able to reach the phloem and consequently did not perform the activities represented by E1 and E2 waveforms, i.e., phloem salivation (during which inoculation of geminiviruses occurs) and phloem sap ingestion (during which geminiviruses are acquired by the whiteflies), respectively. The complete failure of B. tabaci biotype Q adults to feed from the phloem of tomato plants treated with cyantraniliprole could be explained by rapid cessation of ingestion because of the mode of action of this insecticide. Overall, these findings indicated that cyantraniliprole might represent a useful new tool for producers to protect tomato plants from damage by B. tabaci.

The European grapevine moth, Lobesia botrana (Denis & Schiffermuller) (Lepidoptera: Tortricidae), is the key pest of vineyard, Vitis vinifera L. In Italy, failures in field chemical pest control have been recently reported. The susceptibility to insecticides indoxacarb, methoxyfenozide, and emamectin benzoate was then evaluated in a L. botrana population collected from a vineyard in Emilia-Romagna (northeastern Italy) where pest management programs achieved unsatisfactory results. The field trial showed that the indoxacarb efficacy toward L. botrana was very low in the two timings of application (7.9 and -1.5%) in comparison with untreated control, while the efficacy of methoxyfenozide (76.1%) and emamectin benzoate (88.8%) was high. The decreased efficacy of indoxacarb was also supported by the results of the laboratory bioassay on neonate L. botrana larvae, in which the resistance ratio was 72-fold in comparison with that of the susceptible strain.