File:Vanilla culture in Puerto Rico (1948) (20543604876).jpg

Title: Vanilla culture in Puerto Rico
Identifier: CAT31289489 (find matches)
Year: 1948 (1940s)
Authors: Childers, Norman Franklin, 1910-
Subjects: Vanilla; Orchids
Publisher: Washington, D. C. : U. S. Dept. of Agriculture
Contributing Library: U.S. Department of Agriculture, National Agricultural Library
Digitizing Sponsor: U.S. Department of Agriculture, National Agricultural Library

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42 CIRCULAR NO. 2 8, FEDERAL EXPERIMENT STATION (fig. 30) when subjected to direct sunlight for several hours a day, especially when the humidity is low. From these and other unpub- lished data obtained recently, it appears that the shade tree should be pruned to admit from 30 to 50 percent of the sun. If the trees are pruned about 3 months preceding the dry season, it may be necessary to perform a certain amount of thinning 7 or 8 months later to main- tain an optimum amount of light. The rows of vanilla should run east and west if possible, since this furnishes more shade for pruned rows when the sun is lower to the South during the winter season in Puerto Rico.
Text Appearing After Image:
Figure 30.—The three leaves at the right show varied degrees of sunburn injury as compared with the normal leaf on the left. Injury is similar to that caused by the feeding of snails. The snails work in moist cool places, whereas sun- burn usually occurs on exposed vines. If a tall shade tree such as Inga vera is used in addition to a low support plant, careful attention will be needed in pruning both the plants to admit sufficient light to the vanilla. It is highly important not to permit the vanilla to become heavily shaded. Under heavy shade the stems are thin, leaves small, and the fruiting and flowering mediocre. Under too much sunlight, the leaves not only scald and turn yellow, but the plant becomes weak during drought periods and is more susceptible to the root rot disease. In pruning, extreme care must be taken to prevent damage and breakage of vanilla vines. Close supervision of the pruning opera- tion is necessary.

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