In May 1999, in the Kolar district of Karnataka State, Bemisia tabaci numbers on tomato increased by approximately 1,000-fold that observed previously (3). This was associated with an epidemic of severe tomato leaf curl disease that caused complete crop failure. DNAs extracted from 35 symptomatic tomato leaf samples collected within the epidemic region all gave the expected 500 to 600 bp amplicon with begomovirus-specific primers A/B (1). These primers amplify from the conserved nonanucleotide TAATATTAC in the common region of DNA-A to the conserved amino acid sequence CEGPCKYG within the coat protein gene. AluI and TaqI restriction patterns of all 35 polymerase chain reaction (PCR) products were identical. One PCR product from an epidemic (GenBank no. AF321929) and a non-epidemic (AF321930) site (Bangalore) were cloned and sequenced. The two 531-bp inserts showed 96% nucleotide identity to each other and 94% nucleotide identity to the equivalent region of Tomato leaf curl Bangalore virus (ToLCBV-Ban-4) (AF165098), suggesting that the epidemic was caused by an indigenous ToLCBV strain. Adult B. tabaci were collected from tomato plants at nine sites within the epidemic. DNA was extracted from 9 to 13 individuals per site and analyzed by RAPD-PCR using primers OpB20 and OpB11. Eighty to 100% of individuals per site had identical patterns to those of B biotype individuals from Israel and Florida, which were different to the patterns produced by the indigenous Indian B. tabaci. Adult B. tabaci from the epidemic and nonepidemic (Bangalore) regions were cultured separately on zucchini plants (n = 20) vars. Fordhook and Ambassador. Distinct silverleaf symptoms appeared in all plants fed on by the epidemic B. tabaci, but not on those fed on by the nonepidemic whiteflies. Irregular ripening of tomatoes was also a widespread problem in the epidemic area. Cytochrome oxidase I (COI) (720 bp) gene sequences were obtained for epidemic (AF321927) and nonepidemic (AF321928) B. tabaci, which had only 80% nucleotide identity to each other. A GenBank BLAST search showed that the former were most similar to B biotype whitefly from Israel (AF164667; 97%) and Texas (AF164675; 99%). The B biotype transmits Indian ToLCBV (2) and its introduction into India is of great concern as it is already associated with a devastating plant-disease epidemic. References: (1) D. Deng et al. Ann. App. Biol. 125:327, 1994. (2) P. F. McGrath and B. D. Harrison. Ann. App. Biol. 126:307, 1995. (3) H. K. Ramappa et al. Ann. App. Biol. 133:187, 1998.

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In the wake of changing climatic conditions, plants are frequently exposed to a wide range of biotic and abiotic stresses at various stages of their development, all of which negatively affect their growth, development, and productivity. Drought is one of the most devastating abiotic stresses for most cultivated crops, particularly in arid and semiarid environments. Conventional breeding and biotechnological approaches are used to generate drought-tolerant crop plants. However, these techniques are costly and time-consuming. Plant-colonizing microbes, notably, endophytic fungi, have received increasing attention in recent years since they can boost plant growth and yield and can strengthen plant responses to abiotic stress. In this review, we describe these microorganisms and their relationship with host plants, summarize the current knowledge on how they “reprogram” the plants to promote their growth, productivity, and drought tolerance, and explain why they are promising agents in modern agriculture.

Maize (Zea mays L.) crop is attacked by number of fungal, bacterial and viral diseases, out of which banded leaf and sheath blight (BLSB) caused by anastomosis group 1-IA of Rhizoctonia solani f. sp. sasakii Exner. is one of the most widespread and destructive disease of maize in Southeast Asian countries. The occurrence of this disease has also been reported from other parts of the world, which causes significant yield loss up to 100%. R. solani can survive in the soil for several years and able to infect plants belonging to more than 32 families, including many economically important monocots and dicots plants. The severity of the disease favoured by humid weather with temperature around 28°C, poses challenge to maize growers due to its soil borne nature and lack of resistance cultivars. It is indicated that none of the disease management approaches are effective against BLSB. Banded leaf and sheath blight is difficult to control through either fungicide or crop rotation alone. A number of quantitative trait loci (QTLs) controlling BLSB have been identified that would help the development of maize hybrids resistance to this disease. Management of BLSB requires an integrated approach based on the knowledge of each stage of the disease and molecular aspect of maize defence responses against R. solani. Mention conclusion statement and novelty of the work. The present review summarizes consolidated information on distribution, yield loss, symptoms, pathogen life cycle, epidemiology, genetic structure of the pathogen population, molecular aspect of pathogenicity and its integrated management through cultural, biological, chemical and genetic means. The consolidated knowledge presented in this review should help better disease management and reduce crop yield loss due to banded leaf and sheath blight pathogen.