The pepper family are summer and early fall fruiting plants that are very sensitive to their environmental conditions. When cultural conditions are not ideal or get out of balance the plants will under-perform, fail to fruit, die back or invite disease that can hobble or kill the plant. Improper cultural practices and bacterial infections are the most common problems with pepper plants.
Improve soil around weakly performing pepper plants by topdressing with compost and applying a light dose of 10-10-10 slow release fertilizer alongside the plants at the roots. Scratch into the top inch of soil and water in well and do not exceed label recommended dose of fertilizer.
Identify bacterial spot on your peppers by yellowish spots on the leaves and water-soaked-looking leaf margins which dry to holes in the foliage. Inspect peppers for bumps that scab over and may turn whitish or dark with a secondary rot. Treat by pulling all weeds and debris from the soil below, cut away all damaged foliage and fruits; spray a fixed-copper fungicide product as a preventative measure going forward.
Identify blossom end rot by the saturated looking areas that appear at the blossom end of the pepper. These splotches turn brown and rough, then black and mushy with rot. Infected tissues cannot be rehabilitated and must be pruned away and discarded. Prevent recurrence by amending the soil with calcium and keeping the soil evenly moist preventing extremes of drought and over-watering.
Treat whitish furry mold and mildew by watering only at the roots and never overhead of the plant. Keep soil light moist not soaking wet and scale back watering in extremely humid or rainy weather. Clear away all debris under the plants that can harbor spores and prune away any severely infected pepper plant tissues and discard.
Recover from early bloom drop by either reducing the amount of nitrogen fertilizer applied or by moving the plants to a location where temperatures are above 65 degrees but below 90 degrees Fahrenheit.
Prevent sunscald or sunburns on the young pepper flesh by encouraging lots of foliage growth with light nitrogen fertilizer applications of a 10-10-10 formulation and refrain from pruning to ensure leafy green shade cover for the peppers.