CAB Reviews 2016 11, No. 013 A 100 years of biological control of sugarcane pests in India: review and perspective J. Srikanth1*, S. Easwaramoorthy1 and S. K. Jalali2 Address: 1 ICAR-Sugarcane Breeding Institute, Coimbatore, TN 641007, India. 2 ICAR-National Bureau of Agriculturally Important Insects, Bangalore, Karnataka 560024, India. *Correspondence: J. Srikanth. Email: [email protected] Received: 20 October 2015 Accepted: 4 May 2016 doi: 10.1079/PAVSNNR201611013 The electronic version of this article is the definitive one. It is located here: http://www.cabi.org/cabreviews © CAB International 2016 (Online ISSN 1749-8848) Abstract Insect pests constitute a major biotic stress in sugarcane in India as they attack the crop from the time of planting until almost harvest, inflicting yield and sugar losses. Biological control has always received a prominent position among the pest management tools, facilitated by the unique semi-perennial crop habitat and low pesticide usage. Biocontrol research of the early 1930s and 40s was characterized by surveys focusing on identification and studies on the basic biology of natural enemies. Conservation and re-distribution, and introduction and colonization of predominant parasitoids was practiced very early, and even in the recent past, with remarkable success. Mass multiplication and field evaluation that began in the early decades continue today, as is demonstrated by the use of the most exploited parasitoid Trichogramma chilonis. Several parasitoids and predators of borers and sucking pests were investigated systematically when the need arose. Among entomopathogens, granulosis viruses and fungi received considerable attention; a simple formulation of Beauveria brongniartii reached commercial production for the control of the white grub Holotrichia serrata. In recent years, isolates of Bacillus thuringiensis from sugarcane soil have been examined and a scarabaeid-specific cry gene has been identified. Preliminary studies of kairomonal principles from borers as attractants to the larval parasitoid Cotesia flavipes have been carried out. Organizational support to the cause of biological control includes coordinated research efforts from government agencies, production of biocontrol agents by commercial insectaries and promotion of technologies by the sugar industry. In this review, we chronicle the major research findings over the past eight decades, portray an overview of their significance and project the prospects and priorities for biological control research and promotion in the country. Keywords: Sugarcane, Biological control, Historical progress, Organizational support, Sugar industry, Research priorities, Technology transfer Review Methodology: In this review, we present a snapshot account of the decade-wise significant research findings over the last century and an overview of biological control in sugarcane in India. We examined the assortment of literature shown in the section Introduction and also investigated the relevant references in these publications. Further, we searched CAB Abstracts and CAB Abstracts Archives using general keywords such as sugarcane, natural enemies, parasitoids, predators, entomopathogens, biological control, etc. We also used scientific names of individual pests known to occur in the country to obtain abstracts from the CAB databases and searched further within the saved sets of abstracts using terms related to biological control. We also requested and obtained latest publications from colleagues working on sugarcane biological control at our own institute as well as other organizations. Introduction second largest agro-based industry after textiles. Sugarcane also supports two important rural and cottage industries, Sugarcane crop namely jaggery and khandsari (unrefined raw white) sugar. In addition, some by-products of sugar industry, such as As an important commercial crop of Indian agriculture, molasses, bagasse and press-mud, serve as raw material for sugarcane provides raw material to sugar industry, the alcohol-based industry, power generation and organic http://www.cabi.org/cabreviews 2 CAB Reviews fertilizers, respectively. Sugarcane area, production and pro- trophic levels to adopt a strategy of maximizing their repro- ductivity figures have steadily increased over the decades ductive rate (r selection). In contrast, the more uniform alongside the growth of sugar industry. All India estimates climatic and favourable crop growth conditions prevalent for 2013–14 indicated a crop area of 4.99 M ha with throughout the year in the tropical zone apparently govern average cane yield of 70.50 t/ha and sugar recovery of both the pests and natural enemies to maintain their popu- 10.23%. The number of functional sugar mills in the country lations at what can be akin to the carrying capacity of the went up from 29 during 1930–31 to 513 during 2013–14 environment (K selection). Besides, the inclement crop [1]. Cultivated in two broad agro-climatic regions of the canopy in the grand growth period disallows insecticide country, namely tropics and subtropics characterized applications thereby rendering the semi-perennial habitat by moderate or ideal and extremes of climatic conditions, conducive for both natural and applied biological control. accounting for 45 and 55% area, respectively [2], sugarcane Organizational support from government and industry also will continue to remain a major agro-industrial crop of plays an important role in making biological control an the country despite several limitations. implementable reality in sugarcane. The historical roots of biological control in the country date back to 1919 when Misra [13] made some preliminary Insect pest scenario observations on the parasitoids of pyrilla Pyrilla perpusilla Hemiptera: Lophopidae) and whiteflies (Aleurolobus baro- The significant growth in the sugar industry and the densis and Neomaskellia bergii; Hemiptera: Aleyrodidae). expansion of sugarcane cultivation brought in their wake Mass multiplication of Trichogramma chilonis (=evanescens biotic stresses. Amongst these, insect pests, though ranking minutum) on the factitious host Corcyra cephalonica was behind diseases, inflict considerable losses in terms of cane started in the 1930s [14] for use against shoot borer Chilo yield as well as sugar output. Sugarcane displays different infuscatellus (Lepidoptera: Crambidae) in the inundative pest profiles in subtropical and tropical India, albeit with release mode. During 1958–64, Isotima javensis was suc- considerable overlap (Table 1). The hostile climate charac- cessfully established in peninsular India against top borer terized by seasonal extremities in subtropical India supports Scirpophaga excerptalis (Lepidoptera: Crambidae) [15]. moderate crop growth but high pest abundance. In contrast, Similarly, Encarsia flavoscutellum introduced from north- the moderate climate in tropical India favours good crop eastern India [16] established in tropical India and prevented growth but low pest levels [3]. Insect pests attack sugarcane yield and quality losses due to woolly aphid Ceratovacuna from planting to harvest and these include borers, sucking lanigera (Homoptera: Aphididae) [17]. While the biological pests, defoliators and subterranean pests. David and control attempts against top borer with I. javensis, pyrilla Nandagopal [4] provide an exhaustive list of sugarcane using Epiricania melanoleuca [18] and woolly aphid with pests, together with notes on their distribution and keys for E. flavoscutelluam are classic examples of successful intro- identification based on damage symptoms, gross mor- duction and colonization within the country, T. chilonis has phology and feeding habits. David et al. [5] compiled the become synonymous with augmentative use of a mass- sugarcane entomology work conducted in the country and produced parasitoid. The progress of biological control Varma [6] gave a detailed account of pest problems in sub- research in sugarcane in the country has been documented tropical India with notes on their management. Additional as, for example, research publications in periodicals, annual records of pests have been documented subsequently [7]. reports of the All India Coordinated Research Project (AICRP) on Biological Control of Crop Pests and Weeds, Biological control books [5, 10, 11] and bibliographies [19, 20]. Recently, sugarcane entomology work – including biological control – An array of control tools, including resistant cultivars [8] at the Sugarcane Breeding Institute, Coimbatore, Tamil and chemical control [9], is in vogue in sugarcane pest Nadu State, southern India, over the last century was management. Nonetheless, biological control occupies a compiled in the centenary commemorative publication of prominent position, both in theory [10] and practice [11], the institute [21]. The issues and strategies in sugarcane pest owing to several unique features of the crop-pest system. management, with emphasis on biological control, have These include long crop duration, staggered planting in been delineated in yet another centenary publication [22]. synchrony with the crushing schedule of sugar mills, and regenerative ability of the crop that enhances economic thresholds and multitude of pests occurring sequentially Decade-wise progress through the crop phenology supporting the natural enemy continuum, all of which confer on the crop the status of a Prior to 1930 semi-perennial system. Interestingly, key natural enemies, besides the pests themselves,