Investigations of Trichoderma spp. and Beauveria bassiana as biological control agent for Xylotrechus arvicola, a major insect pest in Spanish vineyards.

Xylotrechus arvicola (Olivier) (Coleoptera: Cerambycidae) is an important pest in vineyards (Vitis vinifera) in the main wine-producing regions of Spain. Effective control of this pest is difficult due to the biology of this pest. Biological control agents (BCAs) have proven to be an effective tool in controlling and preventing the spread of a variety of plant pests and diseases. Consequently, the aim of the present study was to assess the capacity of different Trichodema spp., isolated from various vineyards and one commercial isolate of Beauveria bassiana Vuillemin (Hypocreales: Cordycipitaceae), as BCAs of X. arvicola. Isolates of Trichoderma spp. and one isolate of B. bassiana were evaluated against X. arvicola eggs, larvae and adults. Trichoderma harzianum and Trichoderma gamsii demonstrated a good ovicidal control, 100.0% with T. harzianum and over 92.0% with T. gamsii. These Trichoderma strains achieved an over 65.0% larval mortality and 87.5% adult mortality. B. bassiana was the most effective treatment against X. arvicola larvae. These results confirm that Trichoderma spp. can be used to inhibit egg development. In addition, Trichoderma spp. and B. bassiana can help to prevent larvae boring into vines and to kill adults. Therefore, Trichoderma spp., especially T. harzianum and T. gamsii, and B. bassiana can be considered as highly effective BCAs of X. arvicola in vineyards.

Field evaluation of 3-hydroxy-2-hexanone and ethanol as attractants for the cerambycid beetle pest of vineyards, Xylotrechus arvicola.

BACKGROUND: The beetle Xylotrechus arvicola (Coleoptera: Cerambycidae) is a serious pest of vineyards in the Iberian Peninsula. In previous work, the male beetles, but not females, were shown to produce (R)-3-hydroxy-2-hexanone, and female beetles were attracted to this compound in a laboratory bioassay. In this study, release rates of 3-hydroxy-2-hexanone from different dispensers were measured in the laboratory, and the attractiveness of these to X. arvicola adults was determined in trapping tests in three traditional wine-growing regions in Spain. RESULTS: As a result of laboratory experiments, for field experiments 3-hydroxy-2-hexanone was formulated as 100 µL in a polyethylene sachet (50 mm × 50 mm × 250 µm), and ethanol was formulated as 1 mL in a polyethylene press-seal bag (76 mm × 57 mm ×50 µm). Field catches were similar at all three study sites. Catches in traps baited with 3-hydroxy-2-hexanone alone were not significantly different from those in unbaited control traps, but catches in traps baited with 3-hydroxy-2-hexanone and ethanol in separate sachets, with 3-hydroxy-2-hexanone and ethanol in the same sachet or with ethanol alone were significantly greater than those in control traps. These results confirm that the beetles are attracted to ethanol, and the addition of 3-hydroxy-2-hexanone does not seem to make any difference. CONCLUSIONS: Attraction of females for the male-produced compound (R)-3-hydroxy-2-hexanone has been observed in laboratory but not in field experiments. Traps baited with ethanol are highly attractive to both sexes of adults of X. arvicola, and these can be used for improved monitoring of the adult emergence and for population control by mass trapping. © 2016 Society of Chemical Industry.

Reproductive Patterns of Xylotrechus arvicola (Coleoptera: Cerambycidae), an Emerging Pest of Grape-Vines, under Laboratory Conditions.

Xylotrechus arvicola (Olivier) is an emerging pest in vineyards ( Vitis vinifera ) in the Iberian Peninsula. Its reproductive biology has been studied in the laboratory in order to develop pest-control measures. Obtained results show that the oviposition period is significantly longer in wild females (16.6 ± 2.9 d) than in laboratory females (9.7 ± 1.3 d), but there are no significant differences in the egg-hatching periods between the wild and the laboratory females. Fecundity is significantly higher in laboratory females (93.9 ± 12.1 eggs per female) than in wild females (56.8 ± 9.2 eggs per female). On the other hand, viability (percentage of viable eggs per female) is significantly higher in wild females (53.7 ± 6.6%) than in laboratory females (22.9 ± 3.6%). Wild females lay fewer eggs over a longer period, while laboratory females concentrate on laying in the first 6 d. X. arvicola females (wild and laboratory) lay the highest number of eggs on the sixth day. The fecundity and viability of eggs are extended over a longer period in wild females than in laboratory females. So X. arvicola is a species in which larvae feed directly affects reproductive patterns. These results suggest that, when larvae feed directly from the natural host, the fecundity period and the viability of eggs increase. So the selection of a host plant could be influenced by the composition of the wood. This behavior of the species can also help to advance knowledge of the biology and ecology of this pest, to be applied in integrated control.