Studies on Seasonal Incidence and Management of Early Shoot Borer and Top Shoot Borers using New Insecticides in Sugarcane (Saccharum officinarum L.)

Sugarcane (Saccharum officinarum L.)is a tropical plant belonging to the family gramineae. Sugarcane originated in New Guinea, where the cultivated canes were of two main groups: (a) thin, hardy north Indian types Saccharum barberi and the Chinese Saccharum sinenses and (b) thick, juicy noble canes S. officinarum. S. officinarum is highly prized cane. The origin of S. officinarum is Indo-Myanmar China border with New Guinea as the main centre of diversity. The S.officinarum are called the "noble canes' due to thick, juicy, low-fibred canes of high sucrose content. The origin of Saccharum robustum is New Guinea. The origin of Saccharum spontaneum is subtropical India. For cultivation of sugarcane, loam soil of 10-15 percent moisture content is suitable. If the moisture content in soil is low, proper moisture should be maintained. Till deep by disc harrow followed by 2-3 light plough and levelling. Generally the distance between row to row is kept at 90 cm and setts of three buds are used, 37.5 thousand setts or according to thickness 60-65 quintal setts per hectare is used. Before sowing, soak the setts of 2 or 3 buds in water and then treat with mercury chemical (Ariton 6 percent or Anglol 3 percent) of 0.25 percent solution. For seed processing, Bavistin 0.1 percent solution can be used.

Byproducts like molasses is the main raw material for alcohol and alcohol based industries, paper industry, fuel purposes and green tops are used as cattle feed. About two percent of the sugarcane is used as raw and juice (beverage) purpose. Sugarcane contains about 65 percent juice and juice contains 77.88 percent water, 8-12 percent sucrose, 0.3 to 3.0 percent reducing sugar, 0.5-1.0 percent organic substance and 0.2-1.0 percent ash (Sundra, 2001). Theoretically sugarcane gives a yield of 450 t ha-1 per year (Moore 1998) but the average yield of the country is only around 70 t ha-1. The average yield is higher (80 t ha-1) in tropical region than the sub-tropical 55 t ha-1. The low production and the productivity are the end results of various factors. Among the factors responsible, the insect pests problems are prominent (Purbeyet al, 2000). The production and productivity of the sugarcane is affected by many factors viz, soil type, selections of variety, fertilizer management, irrigation management and damaged caused by pests. Sugarcane is attacked by insects however 15 pests are reported to cause considerable loss in yield. The early shoot borer, top shoot borer, Internode borer, white grub, sugarcane pyrilla, white wooly aphid, scale insect and termites these are major pest of sugarcane but the early shoot borer are worst pest responsible for severe damage in early growth stage and yield loss.

Sugarcane by virtue of its long duration is infested by a large number of pests. Many pests start infesting the cane right from the very first day when setts are planted in the soil, and till the crop is harvested. The crop is attacked by a large number of insect pests (David 1990) and among them Lepidopteron tissue borers are considered to be the most destructive. Out of about a dozen tissue borers, damaging sugarcane crop in India, top borer Scirpophaga excerptalis (Walker & Plassey), Chilotumidiscostalis are the most injurious particularly in Bihar (Purbeyet al., 2000) and shoot borer, Chiloinfuscatelhis in Uttar Pradesh and Assam. Among different borers, shoot borer causes 22-33 percent in yield loss (Patil & Hapse, 1981), top borer causes 86 percent in yield loss, stalk borer causes 6.11-10.61 percent in yield loss (Jena &Patnaik, 1996), and root borer causes upto 34.20 percent in yield loss (Pandey et al., 1996). In sucking insects pests Pyrillacauses 28.10 percent in yield loss and 1.60 units of sucrose in juice (Agarwal, 1969), whitefly causes a loss of 23.40 percent in yield & 2.90 units of sucrose in juice (Khanna, 1948). Mealybug causes a decrease in sucrose content by 24.10 while the reduction in brix is 16.20 percent (Kalra& Sidhu 1964) and the thrips cause a loss of 30.77 percent on central leaves of 90 days old crop (Gupta 1996). The damage and loss caused by top borer, (Scirpophaga excerptalis walker) are due to the mortality of shoots and canes and also due to the arrest ingrowth of the later. The mortality of young shoots may go even upto 100 percent as observed in Punjab and Bihar (Anon., 1939; Agarwala and Prasad, 1956). In Tamilnadu, due to low incidence of the pest, 10 percent of the shoots die, while in 3-4 percent further growth is suppressed (Doss, 1954). As the crop grows, the percent mortality of shoots/canes due to borer infestation decreases (Anon., 1939; Agarwala and Prasad, 1956; Agarwal and Siddiqui, 1964). Most of the insecticides used on agricultural crop belong to anyone of the following chemical group viz. organophosphate, carbamates and pyrethroids. The widespread use of structurally similar preparation which have same mode of action carries the risk resistance development. To overcome this, discovery of newer classes of insecticide molecules which belongs to formulation technology, active at low doses and least exposure to an environment and their incorporation in integrated pest management system is gaining importance. Increasing the area under sugarcane crop atone hand and relative paucity of the information regarding new molecules on other hand, the present investigation were therefore undertaken to evaluate the new generation, low dose ecofriendly pesticides viz., Novaluron, Lambda-cyhalothrin, Rynaxypyr, Fipronil, Spinosad, Emamectin benzoate and Acetamiprid with following objectives.

Objective of research: 1) To study these Seasonal incidence of early shoot borer and top shoot borer. 2) To study the efficacy of new insecticide against Early shoot borer, Chilloinfuscatellus (Snellen) and Top shoot borer, Scirpophaga excerptalis (walker). 3) To study the impact of insecticidal treatments on sugarcane yield.