The Entomopathogenic Nematodes H. bacteriophora and S. carpocapsae Inhibit the Activation of proPO System of the Nipa Palm Hispid Octodonta nipae (Coleoptera: Chrysomelidae)

Abstract

Entomopathogenic nematodes are biocontrol agents of invasive insect pests in soil and cryptic habitats. Nipa palm hispid, Octodonta nipae, is a pest of palm trees in Sothern China. To address its increasing damage, environmentally friendly control methods are required. This study aimed to test efficacy of Heterorhabditis bacteriophora and Steinernema carpocapsae on O. nipae and investigated the influence of secondary metabolites, nematodes, and their isolated cuticles on the activation of O. nipae’s prophenoloxidase system using qPCR analysis. Our data revealed that O. nipae were less susceptible to H. bacteriophora than S. carpocapsae and penetrations of infective juveniles were higher with S. carpocapsae treatment than H. bacteriophora. Moreover, expression levels of the serine protease P56, prophenoloxidase activation factor 1, PPO and serine protease inhibitor 28 upon S. carpocapsae and H. bacteriophora infections were generally downregulated at all times. However, upon heating, the cuticles lost their inhibitory effects and resulted in upregulation of the PPO gene. Similarly, the addition of arachidonic acid reversed the process and resulted in the upregulation of the PPO gene compared to the control. Further work is needed to identify toxic substances secreted by these EPNs to evade O. nipae’s immune system.

Molecular Identification of stink bug (Pentatomidae sp. BD39) and pod sucking bug (Mirperus sp.) associated with crops under rotation

“…However, various schemes had been put in place such as medium to large irrigation schemes; FADAMA projects to further boost agricultural production and meet population growth. Several challenges of this agriculture intensi cations to avert the threat in food security in Nigeria includes Soil salinity, decreasing soil and water quality and loss of vegetation and build of up pests and diseases [1,2,3,4,5,6]. Pests and diseases problems in the farms leads to widespread application of chemicals which cause serious cases of poisoning, contamination of the environment and even the increased resistance of pests to the active substances.…”

The Symbiotic Bacteria—Xenorhabdus nematophila All and Photorhabdus luminescens H06 Strongly Affected the Phenoloxidase Activation of Nipa Palm Hispid, Octodonta nipae (Coleoptera: Chrysomelidae) Larvae

“…In recent years, attention has been drawn to nipa palm hispid, Octodonta nipae Maulik (Coleoptera: Chrysomelidae) studies especially on its immune response to pathogens such as nematodes [1][2][3][4][5], bacteria [6], and parasitoid venom [7,8]. Entomopathogenic nematodes (EPN) are roundworm-like organisms, which are found in the soil and are pathogenic to many insect pests.…”