adminpesticides while curbing insecticide resistance.
In a statement this week, TRB Head of Plant Health Services Dr Susan Dimbi said the tests are being conducted at Kutsaga Research Station, to test newer ingredients for aphid and leafminer control.
“The TRB has received inquiries from farmers on the management of leafminer and aphids in tobacco, seedbeds and on the land.
“The standard method as per the Handbook of Recommendations, Section 1, is to apply acephate at the rate of 135g per 100 litres of water in a coarse spray at 200ml per square metre for leafminer control in the seedbed,” Dr Dimbi said.
She, however, reminded farmers that acephate was on the EU list of banned chemicals and would therefore no longer be approved for use on tobacco according to the Pesticide Approval Service Scheme.
Dr Dimbi said on the land, leafminer control was achievable by spraying two to four weeks after planting with acephate at the rate of 90g per 100 litres of water in a volume of 500ml per hectare as a 30cm swathe directly over the plants.
“The main objective of this spray is to protect plants when they are most susceptible to damage.
“In many instances, by the time an infection is noticed, most of the damage would have occurred.
“When tobacco plants are small or growing slowly, leafminer moves rapidly up the plant and attacks the heart causing stunted growth or death of the plant,” she further explained.
Additionally, Dr Dimbi said the removal and destruction of infested leaves and other sources of infestation must be done to reduce the likelihood of further re-infestations.
In conventional seedbeds, dimethoate, thiamethoxam and thiacloprid are registered for aphid control.
Imidacloprid, acetamiprid and thiamethoxam are registered for use in floatbeds.
Dr Dimbi also took the opportunity to remind farmers to adhere to legislated tobacco dead periods and to avoid growing crops in the same family as tobacco on the same farm in the same season to reduce the incidences of leafminer and aphids.
The dead period is the time when there is no tobacco plant growing on the land to reduce the carry over of pests and diseases from one season to the next.
Online Reporter