Within-plant distribution of the leaf miner Tuta absoluta (Meyrick) immatures in processing tomatoes, with notes on plant phenology

This study was carried out to evaluate site preference of tomato leaf miner, Tuta absoluta (Meyrick) (Lepidoptera: Gelechildae), developmental stages on processing tomatoes. Eggs, first- and fourth-instar-caterpillars and pupae, damaging processing tomatoes var. IPA-5, at selected stages (I-before flowering, II-before fruits developed, and Ill-after fruits developed) were examined. Natural oviposition was studied by releasing 3-day-old T. absoluta moths (ca 20-30) in cages under conditions of darkness. At stage I, the females chose the under-side of the leaf for oviposition in the apical part of the plant canopy. However, the number of eggs laid on the under-side of the leaf surface and petioles were similar in the three plant parts. At stages II and III, the means of eggs laid on either the upper- or under-side of leaf surfaces was similar between apical and median plant parts. Eggs recorded on leaf petioles were equal for the three parts (apical, median, basal). Higher first- and fourth-instar-caterpillars numbers were observed on the apical and median plant parts for the three developmental stages. However, fourth-instar-caterpillars were distributed equally on the three plant parts in stage III. Higher pupation at stage I was observed on the apical part, while at stages II and III it was similar among the three plant parts. For all stages, the pupation was higher on leaves, followed by soil, mainstems and fruit (stage III), respectively. Stage III showed a higher number of pupae on the mainstem compared with stages I and II.