Tomato leaves curling usually stem from one of six pest types. Of those six, through client garden audits, I've identified aphids as the top offender 60% of the time. Such a high incidence emphasizes the importance of early detection. From the initial signs of aphids on a given plant or leaf to other plants or leaves throughout the garden can take as little as 48 hours, prevention is pivotal.
Symptom Patterns
- Aphids: Curled leaves with sticky undersides
- Whiteflies: Yellow speckling + upward curl
- Spider mites: Fine webbing between stems
Organic Control Methods
- Spray 2% castile soap solution at dawn
- Release ladybugs (1,000/500 sq ft)
- Apply diatomaceous earth to soil surface
You can avoid outbreaks by checking the undersides of leaves weekly for bugs and leaf miners. I provide customers with 10x hand magnifiers, so they can view spider mite eggs, as they show up as small red dots to the naked eye. I saved one greenhouse, as 80% of plants were saved as thrips were caught before the infected leaves had advanced from silvering to distortion.
Utilize both physical and chemical controls. As an example, a client's interplanted marigolds reduced aphid pressure by 40%. Combine with regular spinosad sprays if necessary for heavy insect infestations. Plan to rotate treatments periodically - monthly is often best. Pests develop resistance much more quickly than most gardeners realize.
Read the full article: Tomato Leaves Curling: Causes and Solutions
