Review of entomopathogenic fungi and nematodes as biological control agents of tephritid fruit flies: current status and a future vision

Abstract

Several fruit fly species (Diptera: Tephritidae) are invasive pests that damage the quality of fruits in horticultural crops and cause significant value losses worldwide.Management of fruit flies mainly depends on conventional insecticides. Unfortunately, the application of synthetic insecticides has caused environmental pollution, risks for humans and animals, and development of resistance. Furthermore, controlling fruit flies by applying synthetic insecticides is challenging because fruit containing third instars often fall from the tree -subsequently the larvae leave the decaying fruits and pupate in the soil. Consequently, both larvae and pupae are protected from surfaceapplied insecticides in fruits and soil. So, there is a pressing need for more eco-friendly and selective control measures with new modes of action. Among such measures are entomopathogenic fungi (EPFs) and nematodes (EPNs). I gathered knowledge on past and present research about EPFs and EPNs as biocontrol agents against fruit flies to investigate approaches that may improve their capacities. I also highlighted several recommendations that may help future field studies on the suppression of fruit fly populations by EPFs and EPNs.

Toxicity of Beauveria bassiana to Bactrocera dorsalis and effects on its natural predators

“…Moreover, Usman et al (2021) and Wakil et al (2022) found that B. dorsalis pupae were more susceptible than larvae, which does not align with our current findings. The contrasting results may be due to differences between the strains of B. bassiana , the method of application, and the age of the pupae ( Rizvi et al, 2009 ; Beris et al, 2013 ; Gul et al, 2015 ; Soliman et al, 2020 ; Shaurub, 2022 ). We focused on one- to two-day-old pupae, whereas previous research showed that the older the pupae, the less susceptible they are to EPF ( Poprawski et al, 1985 ; Hussein et al, 2018 ).…”

“…Temperature and humidity are the most important environmental factors affecting the growth and virulence of B. bassiana ( Dorschner et al, 1991 ; Shaurub, 2022 ). Our results are consistent with Pan et al (2008) , who found that 25°C and 90–100% RH were the optimum temperature and humidity for spore germination and colony growth.…”

Management of Dipteran Pests Through Entomopathogenic Nematodes

“…In addition to performance, factors including cost, availability, compatibility within integrated strategies and alternative options for organic growers will ultimately determine the extent to which nematodes are used against Dipteran insect pests [72, [78][79][80]. To make entomopathogenic nematodes more successful, realistic strategies through genetic engineering [81], IPM programs, and new delivery systems and/or training programs to overcome their inherent cost, formulation instability, and limited field efficacy toward the Dipteran pests are needed [82,83]…”

Natural Warriors against Stored-Grain Pests: The Joint Action of Beauveria bassiana and Steinernema carpocapsae

“…EPNs have been evaluated in combination with insecticides, biocontrol agents, and parasitoids to increase their efficacy against insect pests [ 49 , 99 , 100 , 101 , 102 , 103 ]. Several factors can influence the interaction between EPF and EPNs, such as the species and strains of EPF and EPNs, the target insect host, application parameters, and environmental conditions [ 49 , 103 , 104 , 105 , 106 , 107 ]. The combined use of two biocontrol agents can result in diverse effects on the mortality of the target pests [ 49 , 53 , 89 , 108 , 109 , 110 ].…”