The pepper plants are stunted, and the leaves are crinkled, what’s the problem?
There are a number of factors that contribute to stunting: nematodes (check for knotted/galled roots), under irrigation, over irrigation and lack of fertilizer. The crinkled leaves, however, give a clue in diagnosing the problem. The mosaic virus complex is a common disease of peppers causing green and yellow mottling, crinkling and distortion of the leaves, and stunting of the plant. There is no control for the virus itself. Since viruses are systemic, removing infected leaves or pruning out infected limbs, in the case of a tree, would not be a correct control method.
Insects such as aphids, transmit many viruses, therefore, controlling these pests would help. Removing the surrounding weeds is important since they may harbor the virus, too. The use of a reflective mulch to cover the soil around the plants may be effective in repelling aphids and thus help to limit the mosaic virus.
Lastly, it always helps to plant the right variety. The University of Hawai`i recommends for bell peppers the following varieties: keystone resistant giant, summer sweet 760, grande rio, tambell ll, yolo wonder, California wonder, emerald giant, titan, midway, bell boy hybrid and banana large yellow. The hot peppers recommended are Anaheim chili, Hawaiian chili, jalapeno, long red cayenne and Hungarian. Check with your local University Cooperative Extension office for varieties in your area.