Field performance of entomopathogenic nematodes and an egg parasitoid for suppression of corn borers in Egypt

Abstract

Two entomopathogenic nematodes (EPNs) and an egg parasitoid for controlling three corn borers (Sesamia cretica, Chilo agamemnon and Ostrinia nubilalis) in corn fields. EPNs, Heterorhabditis bacteriophora (BA1) and Steinernema carpocapsae (BA2) were applied to the control S. cretica (after 40 d post planting) on different planting dates. Three releases of Trichogramma evanescens were also conducted at two-week intervals to control C. agamemnon and O. nubilalis starting at tasseling time for the three planting dates; two release levels were used [20 & 30 cards (1000 parasitized eggs/ card)/acre].During the first planting period, the spraying of EPN resulted in a 97% and 100% mortality of S. cretica larvae with H. bacteriophora (BA1) and S. carpocapsae (BA2) respectively, one week post spraying. After two weeks there was a 100% mortality of S. cretica on both EPN species. During the second planting period, the infestation by S. cretica was low, suggesting that this might be a suitable time for planting corn. There were a relatively high number of C. agamemnon and O. nubilalis eggs laid during the third planting period compared to first and second. The parasitism percentages by Trichogramma were high on all planting dates using the 30 cards/acre level compared to the second 20 cards/acre level. At season's end, the numbers of C. agamemnon and O. nubilalis larvae were significantly reduced on the Trichogramma release plots compared to on the control plots. The overall reduction in corn borer larvae on the treated plots using EPNs and later Trichogramma resulted in an increased yield compared to on the control plots. The results suggest that EPN and Trichogramma together can play a crucial role to control the three corn borers.

Side Effects of Insecticides on Natural Enemies and Possibility of Their Integration in Plant Protection Strategies

“…The use of natural enemy agents in combination with selected insecticides, which have no effect on them, is effective in depressing the population density of the pest. Generally, egg parasitoids such as Trichogramma have been widely used as biological control agent as reported by Hassan (1982), Bigler (1984) and El-Wakeil & Hussein (2009); who confirmed that 65 -93% reduction in larval infestations of Ostrinia nubilalis in corn fields was achieved following Trichogramma releases in Germany and Switzerland as well in Egypt.…”

Conservation Biological Control Practices

“…Timing, rate and frequency of release are determined according to the nature of the target pests, natural enemies and crops. Pathogens like entompathogenic nematodes could be applied as sprays or injection [22,106,107]. Examples of cases of NE field releasing are summarized in Table 3.…”

“…The infested plants S. cretica were sprayed one time with 500 and 1000 IJs/ml of Steinernema carpocapsae and Heterorhabditis bacteriophora. Three releases of T. evanescens were conducted to control C. agamemnon and O. nubilalis [22].…”

“…Modern crops are often monocultures in highly specialized production units, where not only crop cultivation but also harvest and packaging techniques are specialized [17][18][19]. The development of farming systems (field or landscape) with greater dependence on ecosystem services, such as biological control of insect pests, should increase the sustainability of agro-ecosystems [20][21][22]. Farming systems like greenhouses, annual crop systems and other practices that end with removing the whole crop after harvesting, may give rise to elimination of biodiversity, and decreasing the population of natural enemies in the fields or in different agricultural environments [23,24], as appeared in Figure 1.…”

Efficacy of Egyptian Parasitic Nematodes, Heterorhabditis bacteriophora (BA1) and Steinernema carpocapsae (BA2) in Bio-control of Economically Important Pests

“…The Entomopathogenic nematodes (EPNs) from the genera Heterorhabditis and Steinernema are obligate lethal parasites of insects and are globally used as safe biocontrol agents against wide range of insect pests (Hussein & El-Mahdi, 2019;Hussein et al, 2015;Nouh & Hussein, 2014;Saleh et al, 2009;El-Wakeil & Hussein, 2009;Ehlers, 2005;Burnell and Stock, 2000;). They occur in most agricultural soils all around the world (Hominick, 2002).…”