My tomato leaves have silvery winding mines and the fruit has small holes with frass. What pest is this and how to manage it?
3 Answers
Those silvery winding tunnels in the leaves and the bored holes with frass in the fruit point to Tuta absoluta, the tomato pinworm, a serious pest that builds up fast. Manage it with monitoring and an integrated approach rather than sprays alone. Use pheromone traps to monitor and mass trap the male moths, raise the nursery under net to start clean, remove and destroy mined leaves and infested fruit and crop residue so the pest does not carry over, and keep the field weed free. Rotate recommended insecticides and biopesticides for Tuta strictly per label and KVK advice and never repeat the same chemical group, because this pest develops resistance quickly. Avoid growing tomato continuously in the same field. Follow the waiting period before harvest carefully since the pest attacks the fruit you sell.
Pheromone traps put up early were my best warning. Once I see the catch rising I act fast, because if I wait till the fruit is bored it is too late and the crop is downgraded. Putting up enough traps for mass trapping also brought the numbers down.
A serious caution on resistance, this pest stops responding to a chemical if you spray it over and over. A few of us in the area sprayed the same product repeatedly and it failed. Rotating the recommended groups and including biopesticides as KVK advised worked far better than just spraying more often.