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Abstract The farmer interest in biological control-based management practices using entomopathogenic fungi (EPF) for the control of many economically important insects has increased. In this process, selection of effective strains of EPF is an important criterion to control the target insect pests in efficient manner. In this context, this research work was formulated to find out environmentally effective strains of EPF in the soils of costal districts of Andhra Pradesh, India. Out of 135 soil samples collected, 9 yielded 9 strains of Lecanicillium lecanii. Among all 9 L. lecanii isolates, the least median lethal concentration (LC50) for 3rd instar larvae of the tobacco caterpillar, Spodoptera litura (Fabricius) (Lepidoptera: Noctuidae), was 1.17 × 106 spores ml−1 in L-8, followed by 1.27 × 106 spores ml−1 in L-5 in an increasing order. Likewise, the median lethal time (LT50) values of different isolates of EPF against the 3rd instar of S. litura were calculated for the uniform highest concentration of 1 × 108 spores ml−1. Among all 9 L. lecanii isolates, the lowest median lethal time (LT50) was observed as 7.70 days by L-8, followed by 7.77 days by L-5 and 8.50 days by L-7.

Abstract In the recent years, the keen interest has been increased towards biological control-based management practices using entomopathogenic fungi (EPF) for the control of many economically important insects. In this management practices, selection of right strains of EPF is an important criteria to control the target pests in effective manner. In this context, this research work was formulated to find out environmentally effective strains of EPF in the soils of costal districts of Andhra Pradesh. Out of 135 soil samples collected, 8 soil samples yielded 8 strains of Metarhizium anisopliae. Among all 8 M. anisopliae isolates, the least median lethal concentration (LC50) for 2nd instar of the tobacco caterpillar, Spodoptera litura (Lepidoptera: Noctuidae) was 1.24 × 105 spores ml-1 in M-7, followed by 1.72 × 105 spores ml-1 in M-5 and 1.86 × 105 spores ml-1 in M-4 in an increasing order. Likewise, the median lethal time (LT50) values of different isolates of EPF against 2nd instar of S.litura were calculated for a uniform highest dose of 1 × 108 spores ml−1. Among all 8 M. anisopliae isolates, the lowest LT50 was observed as 186.44 hours post infection (hpi) with M-5 and 189.34 hpi with M-7.

A field experiment on drip irrigation for Chowghat Orange Dwarf X West Coast Tall (COD X WCT) coconut hybrid was conducted in laterite soil at Central Plantation Crops Research Institute, Kasaragod (Kerala, India) to study the drip irrigation requirement and its influence on growth and yield. The treatments included were three levels of drip irrigation (at 33, 66 and 100% E0 daily), basin irrigation (100% E0) and rainfed control. The experimental results revealed that annual leaf production and leaf nutrient status of coconut palm was significantly higher in the irrigated treatments compared to the rainfed control. The female flower production and nut yield with 66 per cent of Eo was on par with 100 per cent of Eo through drip and 100 per cent of Eo through basin irrigation and significantly superior compared to drip irrigation at 33 per cent of E0 and rainfed control. Drip irrigation equal to 66 per cent of open pan evaporation (Eo) proved to be the economically efficient method of irrigation with water saving of 34 per cent compared to 100 per cent of Eo through basin and drip method.

A field experiment on drip irrigation for Chowghat Orange Dwarf X West Coast Tall (COD X WCT) coconut hybrid was conducted in laterite soil at Central Plantation Crops Research Institute, Kasaragod (Kerala, India) to study the drip irrigation requirement and its influence on growth and yield. The treatments included were three levels of drip irrigation (at 33, 66 and 100% E0 daily), basin irrigation (100% E0) and rainfed control. The experimental results revealed that annual leaf production and leaf nutrient status of coconut palm was significantly higher in the irrigated treatments compared to the rainfed control. The female flower production and nut yield with 66 per cent of Eo was on par with 100 per cent of Eo through drip and 100 per cent of Eo through basin irrigation and significantly superior compared to drip irrigation at 33 per cent of E0 and rainfed control. Drip irrigation equal to 66 per cent of open pan evaporation (Eo) proved to be the economically efficient method of irrigation with water saving of 34 per cent compared to 100 per cent of Eo through basin and drip method.

A field experiment was conducted at Central Plantation Crops Research Institute, Kasaragod, India for six years (1993-1999) to study the impact of drip irrigation levels and mulching on coconut in littoral sandy soil. The treatments consisted of three levels of drip irrigation (66, 100, and 133 % of open pan evaporation (E0)) along with basin irrigation (100 % of E0) and rainfed control as main plot treatments and mulching with coconut leaves and no mulching as sub plot treatments. The experimental results revealed that annual leaf production and leaf nutrient status of coconut was better in the irrigated treatments compared to the rainfed control. The drip irrigation at 66 per cent of E0 (27 litres of water per palm per day during December-January months and 32 litres of water per palm per day during February-May months) resulted in water saving and the nut yield was on par with 100 per cent and 133 per cent of E0 through drip and 100 per cent of E0 through basin irrigation and differed significantly compared to rainfed control. The nut characters like nut weight, husk weight, copra thickness, copra content and copra yield was superior under irrigated treatments compared to rainfed control. The copra yield was 499 kg per ha under rainfed condition, where as it was 2087 to 2202 kg per ha under irrigated treatments. Irrigation along with mulching with coconut leaves resulted in significantly higher nut yields.

Coconut-Based Mixed Farming System which evolved from the Central Plantation Crops Research Institute is one of the technologies recommended for sustainable coconut production. The economic analysis of this system for the period 1989-90 to 1997-98, realized a net return between Rs. 49,700 to Rs. 126,900. The Cash Flow Analysis preformed using a discount rate of 14% realized the Benefit-Cost Ratio (BCR) of 1.36, the Net Present Worth of the system was Rs.286,500,, the Internal Rate of Return was 27.44%, and, the Pay Back Period was five years.

Analysis of past weather data indicated increase in maximum temperature at varied magnitudes over various coconut growing areas across the country except in southern Kerala. In case of minimum temperature, sixty percent of the locations studied showed a declining trend, widening the difference between maximum and minimum temperatures. The days above 33 oC, optimal for coconut growth and development, were in increasing trend in most of the coconut growing area while days below 15 oC are increasing in northern Kerala, plains of Karnataka and western Tamil Nadu. Annual Rainfall showed declining trend in most of the coconut growing areas with change in amount. Dry spells are in increasing trend in parts of Karnataka and Kerala. Change in coconut productivity during past three decades across the country ranged from -114 to 270 nuts/ha/year. The productivity of coconut during the study period was in increasing trend except for parts of Maharastra, Karnataka and Tamil Nadu, where consecutive droughts affected the yields.