Studies on location specific seasonal survey for digital mapping of important cashew diseases

Introduction

Cashew has been an important crop in Konkan region of Maharashtra state. The present study was undertaken to study the variation in disease intensity of cashew in Konkan region of Maharashtra state The variation of disease incidence and severity of disease of cashew resulting from devastating effects of plant pathogens, limits crop productivity globally, thus affecting food security. The effects of globalization, climate change, evolution and new emergence of pathogens, increases the more variation in spread of different plant disease. (Agrios, 2005) [1] . Plant-pathogenic fungal, bacterial and virus growth, development and disease is guided by critical environmental factors and are crucial in limiting the quality and quantity of agricultural produce.(Srinivas 2022). Climate change also disrupts and alters the distribution of different diseases, which poses a threat to agriculture (Rosenzweig et al., 2000; Scherm et al., 2000) [6,7] The season wise climate variation is becoming increasingly extreme and unpredictable (Paul et al., 2009) [5] , Consequently, early detection of pathogens, accurate diagnosis, assessment and its immediate intimation to the beneficiary or farmers is very crucial to undertake prevention and management measures in a particular area. (Myerson and Reaser, 2002) [4] . Lack of these measures will lead directly to inadequate disease control and reductions in crop production and quality. The collection and interpretation of data can be compiled and formatted in to virtual image on computer by producing map is called as digital mapping which will gives quick accurate information of disease status status for the users or beneficiary.(Ann jones et al 2004) [2] . The Digital mapping will help to transfer the technology of cashew disease to enhance the delivery of public services, improve efficiency, and faster transparency (Guler M and Buyukozkon G 2023) [3] . With this view, the efforts have been made to do location specific survey for digital mapping of important disease of cashew in Sindhudurg district during winter and summer season for consequtive two years (2021-22) & (2022-23). The data of different disease collected is compiled and formatted into virtual image and make available for users. The trial has been initiated by selecting the two farmers from each Tehsil of Sindhudurg district so as to conduct the fixed plot survey for digital mapping. The five trees each of cashew were selected and tagged for future monitoring. . On the basis of observations, Percent Disease Incidence (PI) and Percent Disease Index (PDI) of cashew were calculated. (Table no.1,2 3 &4).

The Percent Incidence (PI) and PDI is calculated by following formula.

No. of disease plant part observed Percent Incidence (PI) (%) = X 100 Total number of plant part observed Per cent Disease Index (PDI) was calculated by using the formula.

Sum of all disease ratings PDI (%) = × 100 Total no. of ratings × Maximum disease grade

Results and Discussion

In case of Cashew, during both year, the Kudal and Kankavli Tehsil recorded, high percent disease index of cashew disease such as red rust and branch dying respectively during all recorded seasons. The results also revealed that almost the diseases such as red rust, branch dying, yellow leaf spot and having decreasing trend (2022-23)as compared to previous year (2021-22). All the data has been digitalized in the form of digital mapping.

Conclusion

There is a seasonal variation in the disease intensity of diseases of cashew was found in Sindhudurg district. It is also observed that there is no new emergence of disease. The comparison between 2021-22 and 2022-23 clearly shown that the major diseases such branch dying, red rust get decreases. The apple rot disease is remain unchanged as compared to previous year. The data has been digitalised in the form of digital mapping of cashew disease which gives an instant information for the various farmers across the Sindhudurg district. After getting instant information at one location by cashew growers or expert or researcher through internet mode, he will immediately take precaution of the crop at his farm. This digital mapping will help him for early detection and diagnosis of disease for timely applications of foliar fungicides to avoid devastating losses.

The quick information about the rapid diagnosis of plant pathogens is also critical because some fungicides cannot be applied after a certain stage in plant's maturity.

Acknowledgement

AcknowledgementAuthors are thankful to the number of the selected farmers from Sindhudurg district , Mango Sub-Centre Girye and the Mango Center of Regional Fruit Research Station, Vengurla Maharashtra, India for providing the mango plants to the experiment.

References

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