The responses of Aedes albopictus to sources of oviposition attractants and stimulants were evaluated with a behavioral bioassay in which females att

Control of Grapholita molesta (Busck) (Lepidoptera: Tortricidae), a major pest of stone and pome fruits, is successfully achieved by mating disruption. Under these conditions, tools other than conventional pheromone dispensers are needed for flight monitoring. The objective of the present work was to determine whether plant volatiles synergize male G. molesta attraction to a suboptimal dose of synthetic sex pheromone. The plant blend (referred to as 5VB), a mixture of three green leaf volatiles [(Z)‐3‐hexenyl acetate, (Z)‐3‐hexenol, and (E)‐2‐hexenal] and two aromatics [benzaldehyde (BZA) and benzonitrile (BZN)], was added to the suboptimal pheromone dose (2 ng on filter paper) in log steps (up to 10 000× the pheromone dose) to test synergism of pheromone and plant blends. In addition, the effect of individual plant volatiles on male responses was investigated by adding to the suboptimal pheromone dose each of the four‐compound plant‐volatile blends, resulting from eliminating one volatile from the 5VB at a time, or each plant volatile alone. Flight behaviour and the time to reach the source were recorded. The 5VB alone was not attractive to G. molesta males, but at a ratio of 1:1 000 (Ph:5VB) or higher, the attractiveness of the suboptimal pheromone dose increased, to a level similar to that of the optimal pheromone dose (10 ng). All tested plant volatiles, except BZA, synergized the response to the pheromone when added individually, but only (Z)‐3‐hexenol and BZN did so to a level not significantly different from the Ph:5VB blend. Aromatics had a stronger effect than green leaf volatiles (GLVs), because their removal, but not the removal of GLVs, decreased landing responses. The addition of the 5VB decreased significantly the time males needed to reach the odour source. The observed enhanced male attraction to mixtures of pheromone and plant volatiles will facilitate the development of lures for G. molesta adult flight monitoring.

Transmission of Potato Virus Y (PVY) by several aphid vectors was studied under laboratory and greenhouse conditions to determine vector propensity on sweet pepper ( Capsicum annum L.) plants. Laboratory experiments were conducted with three PVY strains: pepper-PVY pathotype φ (PVY ^φ ) and potato-PVY (ordinary strain, PVY ^∘ , and necrotic-type strain, PVY ^N ). Pepper (‘Yolo Wonder’), tobacco ( Nicotiana tabacum L., ‘xhanthi nc’), and potato ( Solanum tuberosum L., ‘Bintje’) were used as virus sources or test plants, or both. Results showed that both pepper-PVY and potato-PVY strains were transmissible by Myzus persicae Sulzer to pepper plants, although potato-PVY∘ and – PVY ^N are less efficiently transmitted than PVY ^∘ . Transmission tests between different species of aphids using PVY ^∘ -infected pepper and tobacco as source plants indicated that M. persicae was the most efficient vector, followed by Aphis gossypii Glover and Acyrthosiphon pisum Harris. Aphis fabae Scopoli also was capable of transmitting PVY ^∘ , but with much less efficiency. Greenhouse experiments designed to evaluate the dispersion (secondary spread) of PVY by alatae aphids indicated that M. persicae transmitted the virus at the highest rate. Aphis fabae and Aphis gossypii also were able to spread PVY efficiently under test conditions. Previous works indicated that non-colonizer species, principally in the genus Aphis , have much higher alate activity in open field conditions (higher landing rate) than M. persicae . Therefore, much of the natural spread of virus may be by species that are not commonly found feeding on pepper crops.