Biotic mortality factors in field populations of Tuta Absoluta Meyrick (Lepidoptera: Gelechidae) in South Bulgaria

Abstract

The tomato leafminer Tuta absoluta Meyrick is an invasive species for Europe, North Africa and the Middle East, attacking cultivated and wild Solanaceae plants. After it was recorded in Bulgaria in 2009 it spread in all tomato growing regions of the country. The aim of the study was to establish the biotic mortality factors, influencing the field population of the leaf miner in the region of Plovdiv (South Bulgaria). The mortality, caused by predators, parasitoids and pathogens varried from 12.59% in August 2011 to 45.65% in September 2013. During the years the mortality increased from 19.38% in 2011 to 31.57% in 2013. Three insect species (Macrolophus pygmaeus, Nabis sp. and Neochysocharis formosa), and one mite species (Trombidium sp.) were found to feed on the eggs and larvae of the moth. A fungal pathogen (B. bassiana) was isolated from the larvae. For the larval parasitoid N. formosa the tomato leafminer is a new host in Bulgaria. In laboratory tests aimed at evaluating the consumption abilities of the most numerous predator M. Pygmaeus, the nymph killed an average of 40.75 ± 1.61 eggs or 2.25 ± 0.45 larvae of the leaf miner per day, and the adult-respectively 75.88 ± 1.55 and 4.88 ± 0.61.