Pyrethrum is a cash crop grown for its natural pyrethrins which are used in formulating insecticides. It is considered to be amongst the safest insecticides for use around food. It is one of the most commonly used allowed non-synthetic insecticides in certified organic agriculture.
Ecological conditions
Rainfall: At least 750mm well distributed throughout the growing period.
Altitude: 1800–3000m above the sea level
Temperature: Less than 180C for at least six weeks
Soils: The crop prefer fertile, deep, well drained loamy and volcanic soils with PH above 5.6
High altitude clones and varieties
Variety: P4
Clones: SB/66/107, Ma/71/423, Ma/70/1013, Mo/74/223, L/75/477, L/75/487
Medium altitude clones and varieties
Varieties: K218 and K235
Clones: Ks/75/336, Ks/70/64, Ks/75/313, Kr/74/122
Land preparation
Plough the land early during the dry spell to allow stubble enough time to dry. Plough deeply removing all weeds especially the perennial ones. Dig holes that are 10cm wide and 15cm deep, for poor soils add a handful of well decomposed organic manure in the planting holes and mix with soil. Manure application rate is 10 tons per hectare.
Propagation
Its Propagated from clones obtained from mature plants or tissue culture. Raise the clones in the nursery before transplanting to the main seedbed.
Planting
Plant the clones at the onset of rains to optimally utilize the available soil moisture. Plant clones at a spacing of 30cm by 60cm or 30cm by 90cm depending on soil fertility factors. Add 5g of DAP per hole during planting to enhance fast root growth and crop establishment.
Crop management practices
Weeding:
Carry out weeding through tillage using simple tools like fork jembe; remove all the weeds to avoid much competition for crop growth requirements in the field. Weeding should start from the first month of crop establishment until the crop covers the ground in that it can be able to suppress weeds through shading effect.
Under large scale production chemical weed control can be done using herbicides such as sencor, venzar or ronstar.
Earthing up: Carry out earthing up 2-3 months after planting to encourage tillering.
Crop rotation: Rotate the crop once within 3-4 years growing period by growing any crop not related to pyrethrum.
Cutting-back: Cut-back the crop every year towards the dry season. Carry out weeding and earthing up after the practice followed by application of 250-300kg TSP per hectare.
Intercropping: Intercrop pyrethrum with short duration legumes just after cutting-back, this allows maximum land use during the production phase.
Harvesting
Pick flowers ones in every 2-3 weeks when ray florets are horizontal and about 3 rows of disc florets are open. Dry flowers to about 13% moisture content (sun drying).
Uses
Pyrethrum is used in manufacturing aerosols, agricultural pesticides, livestock sprays, powder dusts and mosquito coils
Marketing
Pyrethrum is sold to Pyrethrum Board of Kenya (PBK) through farmers’ cooperative societies.