Activating tomato plant defenses reduces the damage caused by the zoophytophagous mirid Nesidiocoris tenuis

Abstract: Despite the high efficacy of the zoophytophagous Nesidiocoris tenuis as a biological
control agent, one of its drawbacks is its ability to cause damage to tomato plants. Confronted
with sucking insects, tomato plants trigger defense responses, including the production of
antioxidants or the increase of callose depositions to reduce the impact of insect piercing. In
this work, we hypothesized that the damage caused by N. tenuis in tomato plants might be
reduced by increasing the plant defenses. To do so, N. tenuis was released in defensive-induced tomato plants and non-induced control tomato plants under greenhouse conditions. Tomato plants were defensively induced by exposing them to the green leaf volatile (Z)-3-hexenyl propanoate through polymeric dispensers. Nesidiocoris tenuis established in both groups of plants (induced and non-induced), surprisingly the number of individuals was higher in the induced plants. However, as hypothesized, the damage caused by N. tenuis was significantly lower in the defensive-induced plants. In the defense-induced plants, the total number of necrotic rings was reduced by half, but what was even more interesting was that the number of severe, bent, and aborted rings decreased by almost 70 %. This result can be explained by the increase of callose deposition in the induced plants, which helped in regenerating the plant tissue in areas attacked by N. tenuis. Our results, by minimizing the damage caused by N. tenuis in tomatoes, provide an opportunity for enhancing the management of N. tenuis through the activation of the plant’s defenses.