Host adaptation of Tuta absoluta to 10 potential host plants

Objective Tuta absoluta is a highly destructive quarantine pest listed in China’s Category I Crop Pests List. Clarifying its adaptability to various potential hosts can provide theoretical basis for regional pest monitoring, early warning and scientific integrated pest management.

Methods Ten plant species including solanaceous and non-solanaceous crops were selected as test materials. The oviposition preference, developmental duration of each stage, survival rate and age-stage life table parameters of Tuta absoluta on different hosts were measured. One-way ANOVA and jackknife resampling method were adopted to analyze inter-host differences in fitness.

Results Females laid 61.07% of total eggs on Solanum lycopersicum, which was significantly higher than that on other host plants. Eggs were mainly deposited on leaves, with a significantly higher proportion than petioles and stems. The egg developmental period was the longest on Brassica oleracea var. botrytis (5.32 d) and the shortest on Convolvulus arvensis (4.14 d). Larvae fed on Lycium barbarum had the longest developmental duration (13.50 d), followed by tomato, black nightshade and eggplant; six non-solanaceous plants could not support the complete larval development due to insufficient nutrients and defensive secondary metabolites. The pupal duration was the longest on Solanum melongena (6.88 d), and the total pre-adult developmental time reached the maximum on Lycium barbarum (25.18 d). Populations reared on tomato had the highest larval survival rate (80%), pre-adult survival rate (61%), female longevity (9.36 d) and single-female fecundity (153.64 eggs). The net reproductive rate R₀=53.50 and intrinsic rate of increase rm=0.1402 of tomato populations were significantly higher than those of other treatments (P<0.05).

Conclusion Solanum lycopersicum is the optimal host of Tuta absoluta. The pest cannot complete its whole life cycle on six tested non-solanaceous plants. Three solanaceous plants (Solanum nigrum, Solanum melongena, Lycium barbarum) can sustain the full generation development of the pest with strong population expansion potential and high field outbreak risk, which should be included in routine priority monitoring objects. The host fitness differences obtained in this study can supply experimental data for screening botanical repellents, and provide reference for weed management and targeted pest prevention in Xinjiang tomato producing areas.