Pathogenic and Lethal Effects of the Entomopathogenic Nematodes on the Peach Fruit Fly, Bactrocera Zonata (Saunders) and the Cucurbit Fruit Fly, Dacus Ciliatus (Loew) (Diptera : Tephritidae)

Abstract

Laboratory experiments were performed to evaluate the pathogenic and lethal effects of the entomopathogenic nematodes Hb (Heterorhabditis bacteriophora Poinar) and Sc (Steinernema carpocapsae All strains) on the full grown larvae, newly formed pupae and seven days old adults of the peach fruit fly, Bactrocera zonata and the cucurbit fly, Dacus ciliatus. Mortality rates ranged from 9.3 to 42.7%, 12.7 to 52.3 % for the full grown larvae of both B. zonata and D. ciliatus treated by Sc nematode, respectively, and from 67.3 to 100%, from 46.3 to 100% for the full grown larvae of both B. zonata and D. ciliatus treated by Hb nematode, respectively, whereas mortality rates of pupae ranged from 2.7 to 32.7% for the pupae of B. zonata treated by Sc nematode, from 1.7 to 23.3% for the pupae of D. ciliatus treated by Sc nematode , from 12.7 to 51.7 % for the pupae of B. zonata treated by Hb nematode and from 6.3 to 39.3 % for the pupae of B. zonata treated by Hb nematode. Furthermore, the mortality rates varied from 35.0 to 78.7% , 7.7 to 50.3% for 7 days old adults of both B. zonata and D. ciliatus treated by Sc nematode, respectively, 41.7 to 90.3 and 17.0 to 67.7 % for 7 days old adults both B. zonata and D. ciliatus treated by Hb nematode, respectively. LC 50 and LC 90 values were 325.3, 286.2, 1718.6 and 1650.0 IJs/ cm 2 for larvae of B. zonata and D. ciliatus treated with Sc nematode, 28.8, 56.7, 167.2 and 156.1 IJs/cm 2 for larvae of B. zonata and D. ciliatus treated with Hb nematode, 540.2, 447.4, 1785.4 and 2009.8 IJs/ cm 2 for pupae of B. zonata and D. ciliatus treated with Sc nematode, 235.0, 420.8, 1167.0 and 1941.5 IJs/ cm 2 for pupae of B. zonata and D. ciliatus treated with Hb nematode, 116.8, 261.6, 319.3 and 375.0 IJs/ cm 2 for adults of B. zonata and D. ciliatus treated with Sc nematode and 77.3, 196.7, 290.8 and 253.7 IJs/ cm 2 for adults of B. zonata and D. ciliatus treated with Hb nematode, respectively. From the obtained results we can conclude that the entomopathogenic nematodes: Hb Heterorhabditis bacteriophora Poinar) and Sc (Steinernema carpocapsae All strains) were effective on the different stages of B. zonata and D. ciliatus , Hb nematode was more virulent than Sc nematode and the larvae and adults of B. zonata and D. ciliatus were more susceptible to the nematodes infection than the pupae.

Combined application of entomopathogenic nematodes and fungi against fruit flies, Bactrocera zonata and B. dorsalis (Diptera: Tephritidae): laboratory cups to field study

“…Our results indicated that the larval stage was the most susceptible stage, which is in agreement with findings from numerous reports 16,17,39,39,40,59 . These studies showed that the larval stage was found more vulnerable than the pupae stage.…”

“…Our results indicated that the larval stage was the most susceptible stage, which is in agreement with findings from numerous reports. 16,17,39,39,40,59 These studies showed that the larval stage was found more vulnerable than the pupae stage. In accordance with our findings, Gul et al 16 found that larvae of B. zonata were more susceptible than pupae when exposed to different fungi (B. bassiana, M. anisopliae and Isaria fumosorosae).…”

“…Likewise, Mahmoud 65 reported that B. bassiana, M. anisopliae and Lecanicillium muscarium produced greater mortality in larvae of B. zonata compared to pupae. Similar to our findings, Aatif et al 38 determined higher mortality in larvae as compared to pupae of B. dorsalis when exposed to soil previously treated with H. bacteriophora, S. carpocapsae and H. indica.Moreover, Fetoh et al 39 found the larval stage of B. zonata to be more susceptible compared to pupae when exposed to H. bacteriophora and S. carpocapsae.…”

“…These attributes make them exceptional candidates to manage soil‐inhabiting insect pests, 31–36 including fruit flies 18,20,21 . A limited number of studies under laboratory conditions have reported on the efficacy of EPNs as biocontrol agents against B. dorsalis 37,38,21 and B. zonata 39,40,21 …”

“…18,20,21 A limited number of studies under laboratory conditions have reported on the efficacy of EPNs as biocontrol agents against B. dorsalis 37,38,21 and B. zonata. 39,40,21 Given zero tolerance levels for fruit fly maggots inside fruit at many markets, IPM strategies to control these pests may be more effective when applied together. 41 If EPF and EPNs are combined, three types of interactions are possible: synergistic, additive and antagonistic (or inhibitory).…”