The long term effects of Ortho-bux and lindane propoxur on the cocoa ecosystem (1): effects on minor pests and other non target organisms
The effects of two promising miricides, Ortho-bux 2E (280 g.a.i./ha in 112 L of water) and Lindane/Propoxur mixture (140 g.a.i./ha in 112 L of water) on the minor pests and other non-target organisms on cocoa were studied over a period of six years at the Cocoa Research Institute, Tafo, Ghana on Amazon-Trinitario hybrid cocoa (EI: C43/299 x T63/967) which was a six years old at the beginning of the experiment. There were three treatments namely, monthly spraying with Ortho-bux throughout the year (“Maximum” treatment); monthly spraying five times in the year from august to december with Ortho.bux (“R1” treatment) and Lindane/Propoxur (“R2” treatment) and untreated control. Each treatment was replicated ten times in a randomized block design. The insecticides were applied by means of motorized knapsack sprayers (Solo Port 423, using restrictor No. 2). Assessment of insect populations by visual counting on randomly selected trees ip to hand-height level and from terminal branches and buds under binocular microscope was done monthly before spraying. The mealybug, Planococcoides njalensis, was significantly more abundant on the R1 and R2 treatment plots than on the control plots, but population of Planococcus citri decreased on all the plots including the control plots. Generally ants occurred in significantly higher numbers on the “Maximum” treatment plots. Oecophylla longinoda, however, was adversely affected on all tested plots whilst Crematogaster clarivensis occurs in significantly higher numbers on the R2 than on other plots. Ants remained the most abundant insects on all plots throughout the six years, with Crematogaster striatula, Pheidole meagacephaña, Crematogaster africana, Macromischoides aculeatus, Camponotus (Orthonotomyrmex) vividus and O. longinoda as the dominant species. The capsid predators Reduviidae, were not affected by treatments but spiders were favoured by the “Maximum” treatments. Populations of Tyora tessmani, Toxoptera aurantii and Characoma stictigrapta were significantly high on the “Maximum” plots whereas leaf-eating caterpillars, Coleoptera, Tettigoniidae, Stic Coccidae, Termitidae and Marmara were no affected by treatments. With ost of the insects studied, irregular fluctuations in populations occurred but these fluctuations are not attributable to treatments.
| Main Authors: | , |
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| Format: | Texto biblioteca |
| Language: | eng |
| Published: |
Lagos (Nigeria): COPAL,
1984
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| Subjects: | THEOBROMA CACAO, MIRIDAE, INSECTICIDAS, PLAGAS FORESTALES, ANIMALES NOCIVOS, PLANOCOCCUS CITRI, OECOPHYLLA LONGINODA, CREMATOGASTER, PHEIDOLE MEGACEPHALA, CAMPONOTUS, REDUVIIDAE, TOXOPTERA AURANTII, |
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