Chinese researchers have reported the results of trials looking at the effect of mating disruption as a technique to control tomato leafminer (Tuta absoluta) in greenhouse tomatoes.
The group found that the dosage of pheromone (trans-3-cis-8-cis-11-tetradecatriene acetate – E3Z8Z11-14:Ac) in the tube dispensers is closely related to their attractiveness, and therefore the effectiveness of the technique. “Mating disruption (MD) involves releasing a high dosage of insect sex pheromone odour through a dispenser, causing the pheromone plume to spread everywhere in the field to interfere with the calling and mating of moths,” explained lead author Junxia Huang.
The study compared the field trapping of passive PE tube dispensers at different dosages and the adult T. absoluta attraction in tomato greenhouses. When the adult population density was low, the moth-attracting amount of single E3Z8Z11-14:Ac and binary mixtures at a dose of 60-80 mg was the highest, but when the adult population was high, there was no significant difference among different dosages. More-over, in the tests, the results showed that the effect of different dosages of PE dispensers on mating disruption was not significant.
The setting density of the 80 mg PE dispensers significantly affected the amount of moth catches in the greenhouse. Under low-density adult conditions, the correlation curve showed typical competitive mating disruption, whereas under high- density adult conditions.
“This study demonstrated that the passive PE dispensers are [effective in] mating disruption, and that the density of adult T. absolutais an important factor,” explained Junxia Huang. “MD dispensers should be set up at low density or when the young tomato seedlings are transplanted. A total of 900 passive PE tubing dispensers loaded with 80 mg sex pheromone per ha or one active aerosol dispensers per green-house were required to effectively control T. absoluta.”
