Giovanna Tropea Garzia

Can alternative host plant and prey affect phytophagy and biological control by the zoophytophagous mirid Nesidiocoris tenuis

Nesidiocoristenuis (Reuter) (Hemiptera: Miridae) is an important natural enemy of several key arthropod pests. However, in tomato crop this predator can cause economic damage owing to its zoophytophagous behavior. We investigated in laboratory conditions the influence of two alternative plants, Dittrichiaviscosa L. (Asteraceae) and Sesamumindicum (L.) (Pedaliaceae), with or without prey, on N. tenuis damage and its biological control services on Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) eggs. Both D. viscosa and S. indicum, as companion plants in dual-choice bioassays, significantly reduced the damage of the mirid on tomato. S. indicum was more attractive than D. viscosa for feeding and oviposition and its presence did not interfere with the predation on T. absoluta eggs. We also studied the potential of the three plants as preyless rearing substrate for the mirid, and only S. indicum showed to be a suitable host plant for N. tenuis development and oviposition. The potential applications of S. indicum in N. tenuis field management and mass rearing are discussed.

Insights into food webs associated with the South American tomato pinworm: N. tenuis intraguild behaviour

BACKGROUND The complexity of both natural and managed ecosystems involves various forms of interaction among organisms. Two or more species that exploit the same resource can engage in competitive behaviours, usually referred to as intraguild interactions. These can be direct, i.e. one species feeds directly upon the competitor (intraguild predation) or indirect, e.g. when the dominant organism competes for a food source that another organism is feeding upon (kleptoparasitism). We investigated the potential for such interactions in a biological model composed by the South American tomato pinworm, Tuta absoluta, and three of its newly associated natural enemies: the zoophytophagous predator Nesidiocoris tenuis and the two idiobiont ectoparasitoids Bracon nigricans and Necremnus tutae. RESULTS N. tenuis was shown (i) to scavenge on parasitised T. absoluta larvae and (ii) directly to attack and feed upon larvae of both parasitoid species, although at a higher percentage in the case of N. tutae. In the presence of the host plant, the predator reduced the emergence of both B. nigricans and N. tutae adults significantly. CONCLUSION This study stresses the ecological success of a generalist predator over indigenous parasitoids attacking an invasive pest. Moreover, these findings provide potential elements for better design of biological control programmes against T. absoluta.

Repellency of Plant Extracts against the Legume Flower Thrips Megalurothrips sjostedti (Thysanoptera: Thripidae)

Megalurothrips sjostedti Trybom is an important pest of cowpea (Vigna unguiculata L.) in Africa. To propose an alternative to chemical control, the repellency of 24 plant extracts was evaluated against adult female thrips of M. sjostedti in the laboratory. Plant extracts in ethanol were separately applied on a filter paper disk in a still air visual cue olfactometer. The results showed highly significant differences in repellency among extract type, concentration and their interactions. We classified the level of repellency into four categories as strong, good, moderate and weak or non- repellent based on hierarchical ascendant classification. We identified Piper nigrum, Cinnamomum zeylanicum, Cinnamomum cassia as strong repellents. Five extracts were classified as good, eight as moderate and the remaining eight extracts were weak or non-repellent. Repellency of the extracts increased with the concentration suggesting that the behavioral response of M. sjostedti was dose-dependent. Mono- and sesquiterpene hydrocarbon compounds from seven highly repellent extracts were identified by gas chromatography-mass spectrometry (GC/MS). The use of repellent extracts could be useful in developing integrated pest management strategies for thrips on legume crops. In this regard, the specific modes of action of the identified compounds need to be investigated to incorporate them into the existing crop protection strategies.

First record of the Persea Mite Oligonychus perseae (Acari: Tetranychidae) in Italy with a review of the literature

The Persea Mite Oligonychus perseae Tuttle, Baker and Abbatiello, is reported for the first time in Italy. The pest was found on avocado in Sicily (South Italy), in August 2014. The predatory mite Iphiseius degenerans (Berlese) was found in association with O. perseae colonies.

Geographic distribution of Phyllocoptruta oleivora in the Mediterranean Basin, with particular emphasis on Italy

Phyllocoptruta oleivora (Ashmead) is an eriophyid mite extremely dangerous in several Citrus growing areas. During the 60s, its presence was wrongly suspected in Italy, limited to Sicily, but it has never been confirmed later. Since that time, the record of this mite has been confusing often denied often considered true, without any further investigation on this aspect, causing therefore negative effects on the international trade of citrus fruit from Sicily. Authors so started paying attention to the pest distribution in Italy and other Mediterranean areas, and stressed the importance of a correct specific identification based on the real responsible biological agent of an infestation, its economic relevance and implications for phytosanitary regulations.