Prospects for Citrus Limonoids in Insect Pest Management

Abstract

Limonin and other citrus limonoids act as insect repellents, feeding deterrents, growth disrupters, and reproduction inhibitors against several pest species across a wide range of agricultural crops. We have investigated how these allelochemic properties can be deployed as ecologically sound methods of insect pest management and reduce dependence on conventional, synthetic insecticides in potato production. In a multi-stage process of study and product development, we demonstrated that field populations of Colorado potato beetles, Leptinotarsa decemlineata (Say), could be effectively managed using larvicidal applications of limonoids. Adult repellent and oviposition deterrent effects of limonoids can prevent these pests from colonizing and reproducing in potato fields and thereby reduce or eliminate the need for further pest control efforts. Limonoids also appear to act as synergists to enhance the effectiveness of other biological and conventional insecticides. Research and development approaches and limitations of these materials in agricultural pest management are described.The theoretical basis for using natural plant compounds like the citrus limonoids for the management of insect pests is within the concept of coevolution advanced by Ehlrich & Raven in 1964 (/). The coevolutionary process of plants and insects has resulted in a number of plant defenses, including an estimated hundreds of thousands of plant-produced chemicals (2). Plant-feeding insects select and recognize their food based on plant chemical characteristics acting as attractants and phagostimulants that promote host finding and feeding. Other phytochemicals may also inhibit feeding, disrupt growth and development, and modify behavior by acting as insect deterrents, repellents or toxins (3,4,5). The identification and development of these biologically active allelochemicals into effective, insect pest management components have been the goals of natural product chemists, entomologists and agriculturists for decades, but commercial successes have been relatively rare.Synthetic chemical insecticides, with their greater than fifty years of commercial dominance, have set the standards for assessment of all materials for controlling

Interaction of selected terpenoids with two SARS-CoV-2 key therapeutic targets: An in silico study through molecular docking and dynamics simulations

“…The main biological activity associated to these compounds is their insect antifeedant property [ 32 , 33 ]; furthermore, their antitumoral activities have been reported from in vitro and in vivo studies [ 34 ]. These natural products are also readily available from waste products (seeds, peel, molasses, etc.)…”

Identification of Putative Genes Involved in Limonoids Biosynthesis in Citrus by Comparative Transcriptomic Analysis

“…In citrus, limonoids consist of 37 limonoid aglycones and 17 limonoid glucosides ( Alford and Murray, 2000 ; Chowdhury et al, 2003 ; Patil et al, 2009 ). Previous research reported that TFs could regulate multiple genes in the biosynthesis of indole alkaloids ( Van Moerkercke et al, 2015 ), artemisinins ( Yu et al, 2012 ; Zhang et al, 2015 ), anthocyanins ( Butelli et al, 2012 ; Rinaldo et al, 2015 ) and flavonols ( Misra et al, 2010 ; Stracke et al, 2010 ).…”

“…Limonoids are one of the most important classes of phytochemicals predominantly produced in the Rutaceae, Meliaceae, Cneoraceae, and Simaroubaceae families, with citrus being the only one among them that produce edible fruits. Evaluation of the biological activity of citrus limonoids has revealed the potential of these compounds in anticancer, antimicrobial, antioxidant and insecticidal capacities ( Alford and Murray, 2000 ; Chowdhury et al, 2003 ; Ono et al, 2011 ; Kim et al, 2013 ). Limonoids exist in a number of plant organs and tissues such as stems, leaves, seeds and fruit tissues ( McIntosh et al, 1982 ; Rouseff and Nagy, 1982 ; Herman et al, 1989 ; Li et al, 2014 ).…”

Citrus Essential Oils: A Suite of Insecticidal Compounds

“…Progeny deterrent, antifeedant, egg hatching inhibition activity was documented after application of 5-10 μl citronellol against Callosobruchus analis [78]. Compounds like limonoids act as synergists to enhance the activities of other biological and or synthetic insecticides [79]. We recorded medium larvicidal and adulticidal potential of limonene against Aedes aegypti, but found higher toxicity when combined with diallydisulphide and carvone respectively [80].…”