Studies on climatic factors and damage of Tecia solanivora in Ecuador
In Ecuador, observations have shown that only abiotic factors influence population levels of Tecia solanivora (Lepidoptera: Gelechiidae – EPPO A2 list), and that climatic factors were probably the most important. So far, virtually no natural enemies have been found. For example, out of 10,024 larvae collected during 2 years from various parts of the country, only 2 were parasitized by Braconids, 1 by nematodes and 1 by a virus. Field studies were done from July 2000 to July 2001 to determine relationships between the development of T. solanivora populations and climatic factors. 10 potato plots (300 m²) were planted at different dates (every month, starting from March) and population levels were regularly assessed by using pheromone traps (to catch males) and samples of tubers (to count larvae and assess damage). Various climatic parameters were recorded by meteorological stations in each plot (temperatures, relative humidity, precipitations). Results showed that only few correlations could be established between climate and pest populations, and that interactions were quite complex. However, it appeared that there was a strong correlation between tuber damage noted at harvest and climatic variations observed during the first 2 to 3 months of plant growth. Strong correlations were also observed between the infestation of tubers at harvest and flying males captured in pheromone traps; male flights being also significantly impacted by climatic conditions. It is concluded that by using pheromone traps and climatic measures at early flowering (i.e. 2 months before harvest), it should be possible to predict the percentage of infected tubers at harvest.
Sources
Pollet, A.; Barragán, A.; Lagnaoui, A.; Prado, M.; Onore, G.; Aveiga, I.; Lery, X.; Zeddam, J.L. (2003) Predicción de daños de la polilla guatemalteca Tecia solanivora (Povolny) 1973 (Lepidoptera: Gelechiidae) en el Ecuador.
Boletín de Sanidad Vegetal – Plagas, 29(2), 233-242.