The beneficial effects of early mycorrhizal inoculation with two arbuscular fungi, Glomus mosseae (Nicol. and Gerd.) Gerd. and Trappe and Glomus intraradices Schenck and Smith, were evaluated on Myrobalan 29 C (Prunus cerasifera × Prunus munsoniana Wight and Edr.) plum rootstock in soil infested or noninfested with the root lesion nematode Pratylenchus vulnus Allen and Jensen under microplot conditions. During this two year study, mycorrhizal colonization did not affect the number of nematodes per gram of root in plants infected with P. vulnus. In contrast, P. vulnus significantly decreased the percentage of mycorrhizal root colonization. Most elements were within sufficiency levels for plum by foliar analysis, although low P and deficient Fe and Cu levels were detected in P. vulnus treatments. Early mycorrhizal inoculation with G. mosseae favored plant growth after 20 months, but in soils infested by P. vulnus, only G. intraradices increased the tolerance of Myrobalan 29 C plum rootstock to damaging nematode levels by stimulating plant nutrition and vegetative growth.
J. Pinochet, A. Camprubí, C. Calvet, C. Fernández and R. Rodríguez Kábana
W.A. Dozier Jr., R. Rodriguez-Kabana, A.W. Caylor, D.G. Himelrick, N.R. McDaniel and J.A. McGuire
The yellow passionfruit (Passiflora edulis f flavicarpa Degener), a perennial vine grown in the tropics and subtropics, was successfully grown as an annual crop in a temperate zone. Fruit maturity was hastened by ethephon treatments to allow harvest before the mean date of the first killing frost. Maturity was advanced in a linear manner with application rates of 150, 300, and 600 ppm ethephon. Total yield was not affected by ethephon treatment; however, cull fruit producing no juice increased with increasing rates of ethephon, thereby reducing marketable yields. Soluble solids and ascorbic acid contents of the juice were not affected by ethephon treatment. Purple passionfruit (Passiflora edulis Sims) did not produce blossoms.
C. Stevens, V.A. Khan, M.A. Wilson, D. Ploper, P. Backman, J.E. Brown and R. Rodriguez Kabana
The application of plastic mulches, row cover or a combination of the two were evaluated from 1987 to 1991 for reducing early blight of tomatoes and Alternaria leaf spot of okra. Early blight on early season tomatoes (TU-80-130, New Yorker and Floradade) was significantly reduced by the application of black plastic mulch (BM) or BM plus spunbonded polyester row cover (RC) compared to bare soil. Early blight evaluation of late season tomato (Better Boy) showed that BM significantly reduced the incidence and number of lesions per leaf on the fruit clusters compared to bare soil, but the spunbonded polyester RC treatment didn't improve disease reduction of the BM. Alternaria 14 spot of Clemson Spineless okra in 1989 was severe on plant grown in bare soil compared to those grown on BM, BM plus VisPore row cover, clear plastic mulch (CM) and CM plus VisPore RC treatments. These soldier indicted that the application of agriplastic techniques could be used as a new crop management option in an IPM program to reduce the application of foliar fungicides or application of biological control agents.
C. Stevens, V.A. Khan, L.D. Ploper, P. Backman, R. Rodriguez-Kabana, D.J. Collins, J.E. Brown and M.A. Wilson
Combinations of solarized soil (SBS), bare soil control (BS), black plastic mulched soil (BM), row cover (RC), fungicide (chlorothalonil) and biological treatments (Bacillus cereus) were evaluated. SBS vs. BS treatments were main plots, mulch and row covers splitplots and foliage treatments split-splitplots. Application of either foliar treatment was superior to BS. Using a 1/2 rate of fungicide on plants from solarized soil treatments showed equal or comparable reduction of the disease when compared to tomatoes grown in BS with high rates of the fungicide. Combined treatments of solarized + BM, BM with or without RC and low rate of fungicide or biological agent, were the most effective when compared to BS + fungicide, indicating that integration of plasticulture and biological strategies can reduce early blight below the levels of commercial fungicide applied to tomatoes grown on BS.