Pyrethrum: ozone friendly
1991
Kawisi, M. | Jackson, J. (Ministry of Lands, Agriculture and Water Development, Marondera (Zimbabwe). Horticulture Research Institute)
The paper attempts to describe the production and processing of pyrethrum (Chrysanthemum cinerariaefolium [trev]). It briefly describes the market for pyrethrum, that, its commercial value lies in the chemicals known as pyrethrins which are produced in the flower heads. Pyrethrins have a rapid paralysing effect on many insects, have relatively low toxicity to warm blooded animals including humans, do not leave oily residues so are suitable for use in the home, and are rapidly degraded in crop plants and soil so that they do not accumulate in the food chain or in ground water. Ecological requirements of pyrethrum and propagation methods are given in the paper. Little is known about the pests and diseases of pyrethrum in Zimbabwe as little of the crop has been grown in the country. However, very few pests are known to attack pyrethrum. Some of the pests include thrips, red spider mite and termites. Diseases include pyrethrum wilt (Sclerotinia minor), bud disease (Ramularia bullunensis) and false bud diseases. The flowers are harvested without the stalks attached. Pyrethrum is a flower crop and it needs a high labour input for harvesting and detailed care and attention with respect to matters like weeding, harvesting at the right stage and drying, but is fairly undemanding in terms of capital investment other than for planting material, and is tolerant to drought
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