Macrolophus pygmaeus (Rambur) and Nesidiocoris tenuis (Reuter) (Hemiptera: Miridae) predation activity on Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) eggs on tomato fruits of different ripening stages

Abstract: The South American tomato pinworm, Τuta absoluta (Lepidoptera: Gelechiidae), can severely damage tomato plant by infesting all plant parts including fruits in all ripening stages. The zoophytophagous mirid predators, Macrolophus pygmaeus (Μp) and Nesidiocoris tenuis (Nt) can effectively control this pest. However, their ability to locate and consume T. absoluta eggs laid on tomato fruits has not been explored yet. Our study aims to explore the ability of the two predatory species to find and consume T. absoluta eggs on fruits of different ripening stages (green (G), pink (P) and red (R)). Tomato fruits of different ripening stages had been collected from a tomato greenhouse. Four tomato fruits were placed into an entomological cage in six combinations (2G + 2P, 2G + 2R, 2P + 2R, 4G, 4P, 4R). On sepals of each fruit 7 T. absoluta eggs were placed. Then, a previously starved fifth instar nymph of Μp or Nt was released. Cages were maintained under controlled conditions (25 ± 1 °C, 65 ± 5 % RH, 16:8 L:D). After 24 h the egg consumption was recorded by each predator per fruit. Ten replicates (cages) were used per treatment. Results showed that Μp and Nt consumed significantly more eggs on red fruits (16.3 ± 1 and 14.6 ± 0.8, respectively). On four green fruits, Nt consumed significantly more eggs than Μp (9.8 ± 1.2 and 5.2 ± 0.5, respectively). This was further observed when green and pink fruits were offered together. In their combination (2P + 2G) Nt consumed more eggs than Mp. Conclusively, our study reveals that the different fruit ripening stage may differentially influence the foraging behaviour and efficacy of both predators. These results can be valuable in their most effective use in biological control programmes.