An experiment was set up to examine the effectiveness of papaya leaf extracts in controlling cabbage pests (aphids, diamond backmoth, cabbage head caterpillars) and diseases (black rot, downy mildew) on Gloria F1 cabbage variety. The effectiveness of papaya extracts as biostimulants on cabbage agronomic traits (leaf length, leaf width, number of leaves, plant height) and yield were assessed. A completely randomized block design experiment with three treatments (150gl-1, 100gl-1, and 50gl-1) and a control were established at NaCRRI, Namulonge. There was a general reduction in the incidence and severity of cabbage pests and diseases with the higher pawpaw leaf extract concentrations being more effective. The concentration of 150gl-1 pawpaw leaf extract was the most effective concentration against cabbage pests and diseases. Furthermore, the concentration of 150gl-1 pawpaw leaf extract had the best effects on the agronomic traits (leaf length, leaf width, number of leaves, plant height) and yield of cabbage (total yield and marketable cabbage heads). Generally, the concentration of 150gl-1pawpaw leaf extract (P=0.05) had no incidence of aphids and cabbage head caterpillars and a low incidence (P˂0.05) of diamondback moth relative to other treatments. The effectiveness of varying concentrations of pawpaw leaf extracts against cabbage diseases such as; black rot disease and downy mildew were determined on Gloria F1 variety. The concentration of 150gl-1pawpaw leaf extract (P=0.05) had the lowest incidence of black rot disease and downy mildew. The effectiveness of varying concentrations of pawpaw leaf extracts on different agronomic traits of cabbage was determined on Gloria F1 variety. The concentration of 150gl-1pawpaw leaf extract (P=0.05) led to the longest leaf length, widest leaf width and highest plant height relative to other treatments. Generally, all the treatments almost had similar number of leaves. Furthermore, the treatment of 150gl-1pawpaw leaf extract had the highest total yield and number of marketable cabbage heads. A study should be done on the effect of varying concentrations of pawpaw leaf extracts to determine their efficacy against other cabbage pests such as; cabbage white butterfly, cabbage lopper, cabbage cutworms and cross striped cabbage worm. An experiment should be conducted on the effect of varying concentrations of pawpaw leaf extracts on other cabbage diseases such as; bacterial soft rot, black leg, clubrot and alternaria leaf spot. A bio-chemical study should be done in the laboratory to establish the exact amounts of secondary metabolites in the 150gl-1pawpaw leaf extract inorder to come up with a commercial organic pawpaw leaf pesticide against vegetable pests.

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