Risk assessment of various insecticides used for management of Asian citrus psyllid, Diaphorina citri in Florida citrus, against honey bee, Apis mellifera

Abstract

The Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae), is a major pest of citrus trees worldwide. A wide variety of insecticides are used to manage D. citri populations within citrus groves in Florida. However, in areas shared by citrus growers and beekeepers the use of insecticides may increase the risks of Apis mellifera L. (Hymenoptera: Apidae) loss and contaminated honey. The objective of this research was to determine the environmental toxicity of insecticides, spanning five different modes of action used to control D. citri, to A. mellifera. The insecticides investigated were imidacloprid, fenpropathrin, dimethoate, spinetoram and diflubenzuron. In laboratory experiments, LD values were determined and ranged from 0.10 to 0.53 ng/μl for imidacloprid, fenpropathrin, dimethoate and spinetoram. LD values for diflubenzuron were >1000 ng/μl. Also, a hazard quotient was determined and ranged from 1130.43 to 10893.27 for imidacloprid, fenpropathrin, dimethoate, and spinetoram. This quotient was <0.447 for diflubenzuron. In field experiments, residual activity of fenpropathrin and dimethoate applied to citrus caused significant mortality of A. mellifera 3 and 7 days after application. Spinetoram and imidacloprid were moderately toxic to A. mellifera at the recommended rates for D. citri. Diflubenzuron was not toxic to A. mellifera in the field as compared with untreated control plots. Phenoloxidase (PO) activity of A. mellifera was higher than in untreated controls when A. mellifera were exposed to 14 days old residues. The results indicate that diflubenzuron may be safe to apply in citrus when A. mellifera are foraging, while most insecticides used for management of D. citri in citrus are likely hazardous under various exposure scenarios.

THE EFFECTS OF PYRETHRUM EXTRACT ON Galleria mellonella HEMOLYMPH PHENOLOXIDASE ENZYME

“…Our results shown that the pyrethrum extract is effective on phenoloxidase activity at 0.6 mg/ml level (Figure 1). The data obtained from our study confirms the results of Chen et al (2017). The injection of pyrethrum extract at the level of 0.6 mg/ml is inducing PO formation.…”

“…According to Chen et al (2017), fenpropathrin, a type of pyrethrin, also causes an increase in total PO activity in honey bee (Apis mellifera). This increase is due to the moderate inhibition of fenpropatrin on the diphenolase activity of tyrosinase (Tang et al, 2009).…”

Atrazine Exposure Influences Immunity in the Blue Dasher Dragonfly, Pachydiplax longipennis (Odonata: Libellulidae)

“…These results are important because of the paucity of information on invertebrate immunity and atrazine. While the effects of atrazine on vertebrate immunity have received a great deal of attention ( Rohr and McCoy 2010 , Sifkarovski et al 2014 ) and several authors have documented effects of other agrochemicals on invertebrate immune systems ( Chen et al 2017 , Kalita et al 2017 , Zhu et al 2017 ), we did not find studies examining the impact of atrazine on invertebrate immune systems, despite the high levels of use in the United States ( Atwood and Paisley-Jones 2017 ).…”

“…Immune stress from environmental contaminants is likely to place additional strain on this cost/benefit system ( Guedes et al 2016 ). A number of authors have documented the impact of pesticides on economically important terrestrial species ( Chen et al 2017 , Kalita et al 2017 , Zhu et al 2017 ). However, fewer studies have focused on immunological impacts of pesticides on nontarget insect species, particularly in the aquatic environment.…”

Desenvolvimento de estratégias alternativas visando ao controle do huanglongbing

“…No entanto, apesar dessas recomendações serem, atualmente, o que melhor se pode fazer para o manejo adequado do HLB, o uso intensivo de agroquímicos pode ser perigoso para o meio ambiente, contaminando o solo e a água (Ribas & Matsumura, 2009) e causando desequilíbrio ao ecossistema, como a morte das abelhas evidenciada por Chen et al (2017a). As aplicações excessivas destes produtos químicos com o mesmo modo de ação podem levar à forte pressão de seleção de resistência do vetor (Yamamoto et al, 2009;Tiwari et al, 2011;Boina & Bloomquist, 2015).…”