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Litchi (Litchi chinensis) plantations in new areas without any land suitability assessment putting small farmers at risk of economic loss. The unique capability of the Geographical information system (GIS) for integration, analysis, and interpretation of spatial data has been leveraged for the identification, and mapping of potential litchi cultivation zones in India to help farmers and policymakers make informed decisions. Five climate-derived parameters including the number of days per year having a minimum temperature <12 °C (CumD-Tmin < 12), number of days per year having a minimum temperature <0 °C (CumD-Tmin < 0), number of days per year having a mean temperature <20 °C (CumD-Tmean < 20), highest daily maximum temperature (°C) (Thmax) and average annual rainfall (mm), and eight soil parameters viz. soil depth, clay content, slope, stoniness, drainage conditions, pH, electrical conductivity (EC), organic carbon were identified as suitability parameters. Geospatial data at a grid 0.1° × 0.1° of all the identified climate parameters and spatial layers of eight soil data were analysed using Arc-GIS 10.2. The analytical hierarchy process (AHP) was used for assigning relative weightage to the suitability parameters. Using the weighted sum of feature layers, a climate suitability map, a soil suitability map and finally a litchi cultivation potential zones (LCPZs) map were developed. The northward shift of the suitability zone is indicated under climate change projections. The new approach of identifying suitability parameters in relation to the plant's requirement and its integration in GIS using AHP can be extended to other crops and regions. [ABSTRACT FROM AUTHOR]

Experiment was laid out in RBD design with seven treatments comprised of pruning of affected twigs (July & October) and miticides (chlorfenapyr & spiromesifen) sprayed twice in July and once in October months to evaluate the efficacy of various integrated approaches. Results revealed that initial mite infestation ranged from 31.9 to 45.9%. During 2017-18, no mite infestation was recorded from October to fruiting stage in pruning and removal of affected twigs followed by two spraying of chlorfenapyr 10 EC (0.03%) or spiromesifen 22.9 SC (0.034%) at 15 days interval during July and again pruning in October with one spraying of chlorfenapyr or spiromesifen against 89.0% in control at fruiting stage, followed by no pruning in October along with spraying of chlorfenapyr with 7.6% mite infestation at flowering stage. Similar trend in 2018-19 confirmed that pruning in July and October followed spraying of miticides (chlorfenapyr or spiromesifen) twice in July and once in October were highly effective against litchi mite. [ABSTRACT FROM AUTHOR]

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Investigations were undertaken to develop a better understanding of assimilate partitioning behavior in litchi, with respect to the role of stored assimilates translocated from other sources in the plant during the fruiting season. The first experiment examined the fruit growth pattern in the litchi 'Shahi'. The second experiment focused on the limitation of assimilate supply to litchi fruits by leaf removal and girdling. The third experiment was aimed at fulfilling the assimilate requirement of growing litchi bunches through current photosynthesis by foliar application of a photosynthesis enhancer (triacontanol). The fruits exhibited a sigmoidal growth pattern with a phase of rapid growth 40 to 60 days after fruit set. Irrespective of method or distance of source limitation, the maximum percent of fruit drop was observed when the source limitation treatments were imposed 30 days after fruit set. Source limitation at all the distances resulted in significant increases in percent of fruit drop over those with no source limitations. With respect to different treatments, all forms of source limitation resulted in significant increase in fruit drop over the control. The results suggest that a contribution of carbohydrate from current photosynthesis for partial fulfillment of total carbon demand of growing fruits is necessary. Only no limitation of current photosynthesis contributed towards 0% loss in fruit weight while a limitation of carbohydrate translocation (girdling) contributed towards an 8.5% loss in fruit weight. However, under the condition of limited carbohydrate translocation, restriction on current photosynthesis caused a 19.1% loss in average fruit weight. Studies on foliar application of photosynthesis enhancers (triacontanol) on fruit drop in litchi under restricted (girdled) and unrestricted translocation of assimilate from other parts of the plant were conducted. These indicated a reduction in the rate of fruit drop with an increase in the concentration of triacontanol in case of unrestricted translocation of assimilate. However, under restricted assimilate translocation, increasing concentrations of triacontanol did not result in reducing the percent of fruit drop. Hence, the study clearly indicated the major role of translocated assimilates from other plant parts in fulfilling the assimilate demand of growing fruits in litchi where current photosynthesis contributes partially towards assimilate demand. [ABSTRACT FROM AUTHOR]