which disease in this chilly plant and what is solution

Dear Kuldeep The dark colour at certain specified spots on the branches is not a disease, but it is a varietal charecteristic. Not to worry about this. As for flower drop is concerned , maintain proper moisture and apply recommend dose of fertilisers. As for maintaining proper moisture follow this simple technique. Remove top portion of the soil. Take out handful of soil , and try to make into a ball. While making the soil into a ball , if water oozes out , it indicates that moisture is in excess , if you can make the soil into a ball , it indicates that moisture is optimum and does not require irrigation ; and finally if the soil can not be made into a ball , it indicates that the soil is deficient in moisture and requires irrigation. Apart from this , also spray growth promoters/ regulators like 'planofix , several of which are available in the market to reduce flower drop and also increase flower production. Good luck

thank you sir its very helpful