Biological Responses of <I>Rhynchophorus ferrugineus</I> (Coleoptera: Curculionidae) to <I>Steinernema carpocapsae</I> (Nematoda: Steinernematidae)

Abstract

Rhynchophorus ferrugineus (Olivier 1790) (Coleoptera: Curculionidae) is becoming a serious problem in Mediterranean areas where it is well-adapted, and now is present even in the United States (California). The infestations are primarily in urban areas where chemical control is not advisable and million of Euros are spent to control it. The effects of the entomopathogenic nematode Steinernema carpocapsae (Nematoda: Steinernematidae) on mortality, growth, as well as the immune activity of R. ferrugineus larvae, were investigated. R. ferrugineus mortality exhibited a positive trend with the dosage and duration of exposure to S. carpocapsae. The median lethal dose and median lethal time, important to optimize the treatments, were calculated. S. carpocapsae also had a detrimental effect on R. ferrugineus weight. In vivo and in vitro effects of S. carpocapsae on the phagocytic responses of R. ferrugineus hemocytes also were recorded. S. carpocapsae was not encapsulated by R.ferrugineus hemocytes. After 24 h, the number of hemocytes recorded in treated larvae was reduced. To investigate the defensive abilities of R. ferrugineus humoral and cellular immune systems, specifically against the bacterium Xenorhabdus nematophila (Enterobacteraceae), the minimum inhibitory concentration that inhibits bacterial growth was measured. This is the first time that this technique is applied to entomopathogenic bacteria.

Effect of an entomopathogenic nematode,Steinernema carpocapsaeon haemocyte profile and phenoloxidase activity of the Colorado potato beetle,Leptinotarsa decemlineata

“…The parasitism by S. carpocapsae caused a significant decrease in the number of circulating haemocytes also in the case of larvae of R. ferrugineus. In particular, significant declines in the numbers of plasmatocytes and granulocytes were observed (Manachini, Schillaci, & Arizza, 2013).…”

“…It is interesting to note that no haemocytic encapsulation was observed for S. carpocapsae in parasitised R. ferrugineus larvae. No other evident immune reaction by any type of haemocyte towards the EPN was observed (Manachini et al, 2013); however, encapsulation was noticed in R. ferrugineus larvae when the foreign body was the yeast, Saccharomyces cerevisiae (Manachini et al, 2011). Plasmatocytes readily encapsulate targets following granulocyte attachment, indicating that granulocytes produce factors that activate and recruit plasmatocytes (Pech & Strand 1996.…”

Modulation of immune responses of Rhynchophorus ferrugineus (Insecta: Coleoptera) induced by the entomopathogenic nematode Steinernema carpocapsae (Nematoda: Rhabditida)

“…The majority of studies regarding the interaction between EPNs and immune host system, are focused on lepidopteran and dipteran species (Li et al ., ; Castillo et al ., ), few data are available regarding the huge order of Coleoptera. Although studies on the distribution of RPWs (Rugman‐Jones et al ., ) and on the damage caused to palms are available in literature (Gitau et al ., ), data about the immune defenses of this species are scarce (Manachini et al ., , ), thus, we believe that it is important to study this aspect of the physiology of R. ferrugineus with the aim to improve control strategies against this insect pest.…”

Review on the Management of Red Palm Weevil Rhynchophorus ferrugineus Olivier in Date Palm Phoenix dactylifera L

“…Among the potential organisms, fungi were noteworthy to be considered for inclusion in integrated pest management programs R. ferrugineus (Mazza et al, 2014). Previously several biological control agents have been reported against R. ferrugineus ( and Entomo-Pathogenic Nematodes (EPN) are promising (Hanounik 1998;Salama et al,2001;Abbas et al, 2001;Gindin et al,2006;Manachini et al, 2013). However in date palm, deployment of these agents in the fi eld has not been encouraging probably due to the extreme climatic conditions prevailing in the arid regions of the world where date palm is cultivated and also the hidden nature of the pest making it diffi cult for EPNs and EPFs to survive the harsh climatic condition and inability to reach the pest life stages deep into the palm.…”

“…In Spain however on the canary island palm, application of the EPN Steinernema carpocapsae (Weiser) in semi-fi eld trials proved effective against R. ferrugineus with effi cacies of up to 98% and 80%, in both preventive and curative assays, respectively (Llácer et al, 2009). Manachini et al (2013) Identifying and testing heat tolerant strains of EPFs and EPNs suitable for deployment in date plantations of the Middle-East would go a long way in reinforcing the pheromone based R. ferrugineus-IPM strategy currently employed in area wide programmes against this lethal pest.…”