Early insect damage on tomato plants is easier to manage when you identify the pattern before leaves become heavily distorted. Look at the top and underside of leaves, new growth, stems, and nearby soil.
Inspect both sides
Turn over several leaves and look for pinholes, pale stippling, webbing, sticky residue, eggs, or small moving insects. A single damaged leaf is less informative than a repeated pattern across the plant.
Separate chewing from sucking damage
Irregular holes suggest chewing insects, while fine speckles, curling, or yellowing can follow sap-feeding pests. Missing growing tips may point to a larger caterpillar or beetle that should be found by hand.
Check the plant environment
Look for weeds, crowded foliage, and excessive nitrogen growth that shelter pests. Avoid spraying on a guess; identify the pest and protect pollinators before choosing a treatment.
Monitor after inspection
Mark the affected plant and recheck it every day or two. Remove a few badly damaged leaves with clean pruners, discard them away from the garden, and water at the soil line.