The tomato leaf miner moth is changing into more and more difficult for tomato farmers to fight. Nonetheless, CropLife SA says that though some pesticide functions have been ineffective, the pest has not but proven resistance to any energetic substances.
Picture: Lindi Botha
In a webinar hosted by CropLife SA in September, farmers had been cautioned to implement good stewardship practices to stop tomato leaf miner (Tuta absoluta) from creating resistance in opposition to pesticides.
- absoluta is a extremely harmful pest in South Africa, affecting principally tomato crops and inflicting as much as 100% crop losses. Since tomatoes are a key crop for meals safety and revenue era, the pest presents a significant problem to native producers.
Talking through the webinar, Hamish Ramanand, stewardship specialist at CropLife SA, mentioned there have been no tomato varieties that had been immune to the pest, and that since registered crop safety chemical compounds had been restricted, farmers wanted to be aware to rotate energetic substances to stop chemical resistance.
He clarified that, regardless of many studies from producers that chemical compounds had been ineffective, there was no proof that T. absoluta had change into immune to pesticides.
“Incidents the place there was no knock-down impact after making use of pesticides had been discovered to be a results of incorrect functions and dosages. It’s due to this fact important that farmers observe the right dosage charges and repeatedly calibrate spray gear to make sure it’s functioning correctly,” Ramanand defined.
Nonetheless, he famous that sensitivity shifts had been noticed, which meant the knock-down impact was decreased after making use of pesticides. This was due to overapplication of the identical energetic substances, in addition to improper functions.
- absoluta additionally carries a excessive threat of creating resistance due to its quick lifecycle.
“Farmers have to be very cautious of their administration practices to stop sensitivity shifts or resistance. Rotate energetic substances, don’t return to the precise ingredient earlier than 60 days, and observe the dosage directions.
“Cultural practices like destroying all contaminated materials, crop rotation, or leaving fields fallow for a minimum of six weeks are additionally very important within the combat in opposition to T. absoluta,” Ramanand mentioned.
For the reason that moth additionally feeds on weeds within the Solanaceae household, fields must also be cleared of those weeds throughout crop rotation cycles.
Growing and registering new pesticides is a long-term and dear course of, and farmers are unlikely to see new chemical choices anytime quickly.
Subsequently, Ramanand mentioned producers wanted to develop built-in pest administration (IPM) methods. Along with accountable chemical use, pest monitoring and organic choices must also be applied. This included utilizing pheromone traps that lured moths in order that threshold ranges might be monitored, and farmers throughout an entire space might be notified if there was an outbreak.
Pure enemies like parasitoids and helpful micro organism may be used to stop large-scale outbreaks. Ramanand famous, nevertheless, that reliance on pure enemies fully was not sufficient to manage the pest.
“Farmers want a full IPM programme to handle pests throughout the entire lifecycle. Simply spraying when numbers are excessive is expensive and might do extra hurt than good,” he defined.
