Management of papaya ringspot by isolation and intercropping of papaya
1996
Opina, O.S. | Tomines, R.L. (Philippines Univ. Los Banos, College, Laguna (Philippines). Dept. of Plant Pathology)
The effects of crop isolation, intercropping and canopy structures of intercrop on the epidemic development of papaya ringspot (PRS) was examined under farmers' field conditions. Degree of crop isolation from PRS was achieved by varying the relative distances of potential inoculum point sources from each papaya field. Crop canopy structures were altered by using crops with different canopy indeces and heights. The progressions of PRS were monitored under the conditions described above. Results showed that crop isolation and intercropping of papaya with crops having different canopy structures significantly delayed the onset and reduced the rate of PRS progression. The distance of potential inoculum sources from the papaya fields significantly delayed the disease onset by 10 and 14 weeks when the potential inoculum sources were located beyond 100 and 500 m, respectively, from the papaya fields. It was apparent that the effect of intercropping was less related to the kind of crop planted along papaya, but rather more associated with the canopy structures of the crop such as canopy index or the ratio of canopy coverage relative to the ground area and crop height. Crop height appeared to exert more effects compared with canopy index. Higher crop canopy significantly delayed and reduced the rate of PRS progression, but further reduction of infection rate was achieved by increasing the canopy index. This tudy clearly demonstrated the feasibility of satisfactory PRS management by integrating strict sanitation practices, crop isolation and intercropping of papaya with crops having greater height and canopy index
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