Agriculture Specialist Writer
Kutsaga Research has urged tobacco farmers to adopt effective measures to control mealy bugs infestations that may compromise the targeted 4, 5 tonnes per hectare yields this season.
In a notice to growers recently, Kutsaga Research head plant health and agriculture resilience, Dr Cleopas Chinheya said the pests had the long-term effect of reduced biomass and loss in leaf quality.
"Mealy bug damage in tobacco has been observed from transplanting right up to the curing stage in the barns if the pest is not treated.
"They feed by sucking phloem sap from the leaves, which causes them to turn yellow, wilt then dry," he said.
Although mealy bugs are historically not a common pest of tobacco, their first cases were reported in the 2019/20 season with sporadic incidences reported in Mt Darwin, Shamva, Mhangura, Mutoko and Nyamajura.
Dr Chinheya said an integrated pest management approach was essential for the effective control of the pest.
"Tobacco growers are encouraged to adhere to the recommended cultural practices such as following the ideal crop rotations, agro-chemical rotation schemes and stipulated planting and sowing dates that have traditionally been successfully used to manage pests and diseases. Furthermore, systemic active ingredients are effective for the management of sap sucking insect pests, especially mealy bugs," he added.
Research has shown that once the mealy bugs develop a waxy cuticle, contact insecticides are prevented from penetrating the skin of the insects making it difficult to control them.
Results from the efficacy trial have shown that Imidacloprid plus ßcyfluthrin, Acetamiprid plus Abamectin, Emamectin Benzoate plus Acetamiprid, Lambda-cyhalothrin plus Acetamiprid and Dimethoate were effective in controlling mealy bugs in tobacco.
Growers must apply the chemicals immediately after planting and at two to four weeks post-planting and to report mealy bug incidences on tobacco to Kutsaga as soon as they notice them.
Kutsaga further urged growers to only use registered pesticides from the list of approved agro-chemicals and desist from using unregistered products.
The research institute has since released varieties boasting a yield a potential of 4, 5 tonnes per hectare yet current productivity figures are around two tonnes per hectare.
In 2021, the Government came up with the tobacco value chain transformation plan (TVCTP), which seeks to achieve a US$5 billion tobacco industry by 2025 through localisation of tobacco funding, sustained production of 300 million kilogrammes of the golden leaf, value addition, beneficiation and export of cigarettes.
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In the 2022/23 season the country produced over 296 million kilogrammes of tobacco worth US$897 million from 147 867 growers. This broke the all-time record of 259 million kilogrammes in 2019 and saw productivity increasing from 1, 9 tonnes per hectare in 2021/22 season to 2, 5.
For the 2023/24 season 115 114 growers planted 113 101 hectares of tobacco with 91 percent of them producing under contract. The season was, however, ravaged by the El Nino-inspired drought with yields reaching 232 million kilogrammes worth US$800 million.
