Evaluation of Chrysoperla carnea and Macrolophus pygmaeus as biological control agents of Frankliniella occidentalis on Batavia lettuce under hydroponic cultivation

Few studies have investigated the efficacy of natural enemies against pests in hydroponic farming. We aimed to determine the effectiveness of two predators Chrysoperla carnea (Stephens) (Neuroptera: Chrysopidae), and Macrolophus pygmaeus Rambur (Hemiptera: Miridae), for controlling Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) in hydroponic cultures of Batavia lettuce. Both C. carnea and M. pygmaeus were released weekly with spot treatment: 10-20 individuals /m2 and 0.25-5 individuals/ m2/release, respectively. One of the more substantial conclusions from our current study is that C. carnea and M. pygmaeus highly reduced the F. occidentalis larvae and adults (45.85 and 60.91%) over the control treatments. The efficiency of M. pygmaeus was higher than that of C. carnea. The population of F. occidentalis decreased from 8.75, 7.75, and 7.5 individuals /leaf in control to 8.25, 7.0, 6.25, and 3.5, 3, and 2.5 individuals/leaf in the C. carnea and M. pygmaeus, respectively in all three planting cycles. Results also showed that in control and M. pygmaeus, the variation was only significant between cycles 1 and 3. While the C. carnea group showed a significant difference between cycles 1 and 3 and 1 and 2. Results also indicated that M. pygmaeus was more effective than C. carnea as a biocontrol agent against the larvae and mature F. occidentalis. Thus, using M. pygmaeus and C. carnea to manage the thrips damage is advised.