Entomopathogenic Nematodes on Control of Mediterranean Fruit Fly (Diptera: Tephritidae)

Abstract

Mediterranean fruit fly (Ceratitis capitata) is one of the world's major pests infesting fruit crops, causing significant losses. However, this insect has a soil phase and is a potential target for entomopathogenic nematodes. The objective of this work was to test the efficiency of the nematodes Steinernema carpocapsae ALL and Heterorhabditis amazonensis JPM4 in controlling larvae and pupae of Ceratitis capitata. Petri dishes with filter paper or pots with 200 g of soil were used to assess different nematode concentrations; 20 individuals (larvae or pupae) were placed in each container and the nematode suspension was applied at concentrations of 0, 140, 180, 220, 260, and 300 IJs (infective juveniles) cm-2. The nematode horizontal movement was tested using pots with soil and a metal screen at every 10 cm to define different distances (0, 10, 20, and 30 cm from the application site). Ten larvae and ten pupae were transferred to every distance; 10 mL of the nematode suspension (220 IJs cm-2) were applied at the distance zero; 10 mL of the nematode suspension with 220 IJs cm-2 was applied to each pot, using ten larvae and ten pupae for each evaluation time (0, 10, 20, and 30 days after application of nematodes) to study the effectiveness of these nematodes over time. Both nematodes killed C. capitata larvae and pupae, but S. carpocapsae ALL was the most effective. However, this nematode showed no ability for horizontal movement, which was found in H. amazonensis JPM4 nematodes. Both nematodes showed decreasing efficiency over time.

Virulence of four entomopathogenic nematode against different stages of the Mediterranean fruit fly, Ceratitis capitata Wiedemann (Diptera: Tephritidae)

“…Pupariating larvae and adult flies were susceptible to all nematode infection, with no infection was recorded for the pupae. Rohde et al (2020)…”

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

“…The relationship of fruit fly mortality to concentrations of IJ nematodes is complex, sometimes showing increased mortality from low to moderate densities (Minas et al, 2016; Godjo et al, 2018; Usman et al, 2020b; Jean‐Baptiste et al, 2021; Shaurub et al, 2021; Aryal et al, 2022), followed by decreases at very high densities (Mokrini et al, 2020; Rohde et al, 2020). Variable factors act in combination to induce EPN pathogenicity to hosts, including suppression of the immune system, nutrient depletion, enzyme inhibition, reduction of nutritional metabolism, and toxin production by symbiotic bacteria (Poinar, 1990; Ayad et al, 2001; Shaurub et al, 2015, 2020).…”

“…Pathogenicity of EPNs is developmental stage‐ and age‐dependent. Fruit fly larvae are more susceptible to EPNs than pupae, and young pupae are more susceptible than older pupae (Gazit et al, 2000; Heve et al, 2017; Rohde et al, 2020; Shaurub et al, 2021). The higher susceptibility of larvae compared to pupae may be due to their locomotor activity and higher release of CO 2 , which attracts nematodes (Shapiro‐Ilan et al, 2017).…”

“…The higher susceptibility of larvae compared to pupae may be due to their locomotor activity and higher release of CO 2 , which attracts nematodes (Shapiro‐Ilan et al, 2017). Moreover, larvae have less sclerotized integuments and large natural openings, facilitating insect infection with nematodes (Minas et al, 2016; Rohde et al, 2020). These factors could synergistically increase the susceptibility of larvae to EPNs.…”

“…Cruiser strategist nematodes, those that actively search for a host, demonstrate a greater probability of finding hosts with cryptic or sedentary habits (e.g., pupariating larvae and pupae), whereas ambusher strategist nematodes, those that sit and wait for hosts in order to attack, are more effective in finding high‐mobility hosts (e.g., larvae; Lewis et al, 2006). Under laboratory conditions, ambusher strategist nematodes S. carpocapsae kill C. capitata larvae in the site where nematodes were applied, whereas cruiser strategist nematodes Heterorhabditis taysearae Shamseldean et al and Heterorhabditis amazonensis Andaló, Nguyen & Moino kill B. dorsalis and C. capitata larvae, respectively, up to 20 cm away from the nematode application site (Godjo et al, 2018; Rohde et al, 2020). Under field conditions, using infected host cadavers containing the cruiser strategist nematodes H. baujardi LPP7, the highest average number of recovered IJs was found at 90 cm from the cadaver application point (Del Valle et al, 2008).…”