From page 371 stability, improving soil fertility through enhanced soil organic matter content and nitrogen fixation. It also serves as a highly nutritious animal feed and effectively suppresses striga weeds. Another plant showing good repellent properties is molasses grass( Melinus minutiflora), a nutritious animal feed with tick-repelling and stem borer larval parasitoid attractive properties. Stem borer females that are ready to lay their eggs are repelled from the main crop and are simultaneously attracted to the trap crop. Napier grass produces significantly higher levels of attractive volatile compounds, cues used by gravid stem borer females to locate host plants, than maize. Legumes in the Desmodium genus( silverleaf, D uncinatum and greenleaf, D intortum), on the other hand, produce repellent volatile chemicals that push away the stem borer moths. Desmodium also controls
One of the biggest dangers when buying breeding livestock is that they can look completely normal, but can be carrying a deadly disease with huge financial implications for the unwitting buyer. Paratuberculosis or Johne ' s disease affects cattle, sheep, goats and certain wild animal species. The disease is of long duration and may cause diarrhoea and loss of mass in
striga, which is a parasitic plant, resulting in significant yield increases of the main crop. The use of a combination of these types of plants, ie push and pull plants, leads to greater effectiveness in biocontrol. It constitutes an integrated system that addresses concurrently older( from two years on) animals. The diarrhoea cannot be treated. The time before the disease becomes apparent in a herd varies from less than six months to several years( even
problems of stem borers, striga weed, soil fertility and soil moisture retention, with the added benefit of the leguminous intercrop providing nutritious animal fodder. This method of pest control was developed in Kenya at the International Centre of Insect Physiology & Ecology.
LIVESTOCK
Hidden killer: Ovine Johne’ s disease
PUSH-PULL PLANTING up to 15 years). A very small percentage of the animals show clinical signs. What is Johne ' s disease? ❑ Johne ' s( pronounced“ yohneez”) disease is a chronic( long-standing) disease of the intestine. ❑ It causes reduced weight gain, and steady loss of body condition and body weight leading to emaciation. Q❑
It often causes scouring, especially in cattle and goats. ❑ It is incurable. Once signs appear death is inevitable within weeks or months. ❑ Treatments have no lasting effect on the course of the
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