(1) Background: Tomato leaf curl New Delhi virus (ToLCNDV), transmitted by tobacco whitefly (Bemisia tabaci Gennadius) (Hemiptera: Aleyrodidae), is of major concern in the cultivation of zucchini. The threat of this virus motivates reliance on chemical vector control but European consumers’ demands for vegetables grown free of pesticides provides an important incentive for alternative pest management; (2) Methods: Different whitefly management strategies and ToLCNDV incidences were surveyed in commercial zucchini greenhouses in south-east Spain. In an experimental greenhouse, three different whitefly control strategies, biological, chemical, and integrated (IPM), were evaluated in a replicated trial to determine the most effective strategy for virus suppression (3) Results: Whitefly was present in all commercial zucchini crops surveyed, whereas fewer crops had Amblyseius swirskii or other natural enemies. During three consecutive years, pest management was increasingly based on chemical treatments. Yet, ToLCNDV was widespread in zucchini greenhouses. Experimental results showed that the order of best strategy for virus suppressing was integrated management (73%) > biological control (58%) > chemical control (44%); and (4) Conclusions: IPM was the best strategy for virus suppression. The results can assist in the design of appropriate control strategies for chemical pesticide reduction and decision-making in pest management.

The red palm weevil, Rhynchophorus ferrugineus Olivier (Coleoptera: Curculionidae), is an economically important pest of palms worldwide. To better understand the phenology of R. ferrugineus populations in the Mediterranean basin, the objective of the present work has been to estimate the effect of temperatures within the range 10-25°C on the reproductive parameters of R. ferrugineus and to determine its lower temperature thresholds for oviposition and egg hatching. Our results confirm that oviposition in R. ferrugineus is strongly affected by temperature. Lower thresholds for oviposition and egg hatching (15.45°and 13.95°C, respectively) are below the mean monthly temperatures registered in winter in most of the northern shore of the Mediterranean basin. Under these circumstances, new palm infestations would be difficult during most of the winter. These results should be taken into account when planning some palm management practices, such as pruning or pesticide treatments, in areas under a Mediterranean climate.

The red palm weevil, Rhynchophorus ferrugineus (Olivier) (Coleoptera, Curculionidae), has been present in Andalusia since 1993 although its major expansion began in 2005. Currently, the implementation of an action protocol against the red palm weevil based on curative and preventive treatments has a high cost. The aim of this work is to establish a minimum frequency between preventive treatments that would reduce costs. Three frequencies of application were evaluated (at 45, 60 and 90 days).The results show that preventive treatments can decrease the reproductive potential of the pest, but do not prevent the infestation of palm trees. Preventive treatments every 60 days effectively reduce costs and increase the survival of the palm trees.

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1. To improve biological control and habitat management, how pest predators spread from natural habitats to crops must be understood. We studied whether intrinsic differences in stable-isotopic ratios of C and N from an artificial C 4 (sugar-cane) or C 3 (muti-flower honey) diet could help mark and track predators that feed on them.2. Two aphid predators solely feeding on sugar resources as adults were used: the green lacewing Chrysoperla carnea s.l., and the parasitic wasp Aphidius colemani.δ 13 C and δ1 5 N values from wild individuals helped distinguish them from marked ones and determine the habitat resources they used.3. Green lacewings fed on C 4 showed significantly higher δ 13 C values than those on C3 and wild individuals. However, parasitoid values were unaffected, with no mark acquired. Logistic regression was fitted to assess the probability of green lacewings having either diet with a probability of 0.93. Marks were acquired after 5 days and were detectable 20 days after switching diets with a probability of 0.67. Similar δ 15 N values for both wild populations indicated both predators had similar prey, but different vegetal resources (different δ 13 C values).4. Sugar-cane honey is a natural and reliable marker for tracking lacewing populations in the field, but not for parasitoids. ResumenConocer c omo los enemigos naturales de plagas se mueven desde los hábitats naturales hasta los cultivos resulta fundamental para mejorar el control biol ogico y la gesti on del hábitat. Estudiamos si las diferencias intrínsecas en las proporciones de is otopos estables Carmen Robles-Vallet and Estefanía Rodríguez are first authors.