Evaluation of the potential of predatory mirid bug, Dortus primarius Distant as biocontrol agent of Tuta absoluta Meyrick

Dortus primarius (Distant) a general predator of thrips, lepidopteran eggs, etc., has been observed feeding on South American tomato leafminer, Tuta absoluta (Meyrick), in the laboratory. The efficiency of this indigenous predator against T. absoluta needs to be investigated. Therefore, a series of experiments, viz. developmental time, functional response and population dynamics studies, were conducted to evaluate its potential. This predator could develop on both T. absoluta eggs and first-instar larvae. However, the survival rate of nymphs was higher (93.3%) when reared on eggs compared to first-instar larvae (33.3%) of T. absoluta. A nymph consumed 329.6 ± 5.91 T. absoluta eggs during its developmental period. In a functional response study, both 5th-instar nymphs and adult females showed a type III functional response when exposed to different densities of T. absoluta eggs. At the highest egg density (250), D. primarius adult female and 5th-instar nymph consumed an average of 128 and 114 T. absoluta eggs, respectively. Both adult female and 5th-instar nymph did not differ in handling time (T_h) for T. absoluta eggs (T_h = 0.007). Our greenhouse studies revealed a low population density of T. absoluta in both the treatments with high and low release rates of D. primarius compared to the control treatment. Moreover, it is also clear from the study that establishing this predator before pest arrival helps in reducing the T. absoluta population. These studies give insight into the potential of D. primarius against T. absoluta. However, further investigations must include other interventions along with this predator for better commercial greenhouse tomato crop results.