To control leaf rollers, methods include using Bacillus thuringiensis (BT) for recurring issues, applied when larvae hatch, and spraying horticultural oil on infested trees.
Leaf roller caterpillars can be a nuisance in gardens and on trees, causing damage by rolling up leaves and feeding inside. Fortunately, there are effective control methods available. Based on information from durhammastergardeners.com, two key approaches are recommended for managing these pests:
Effective Control Methods for Leaf Rollers
Controlling leaf rollers often involves targeting them when they are most vulnerable, typically during their larval stage.
1. Utilizing Bacillus thuringiensis (BT)
Bacillus thuringiensis (BT) is a naturally occurring bacterium that is highly effective against certain types of insect larvae, including leaf rollers.
- Effectiveness: BT is particularly useful for recurring problems with leaf rollers.
- Application Timing: For best results, BT should be applied as soon as the larvae hatch. This ensures the caterpillars ingest the BT while they are actively feeding.
- How it Works: When caterpillars consume leaves treated with BT, the bacteria produce toxins that disrupt their digestive system, causing them to stop feeding and eventually die.
2. Applying Horticultural Oil
Horticultural oils, also known as dormant oils or summer oils depending on their formulation and application time, can also be used to manage leaf rollers.
- Application: Trees infested with leafrollers can furthermore be sprayed with horticultural oil.
- How it Works: Oils work by suffocating insects and their eggs. When applied, they block the spiracles (breathing pores) of the pests.
Summary of Control Methods:
| Method | Target Pests | Application Timing | Best Used For |
|---|---|---|---|
| Bacillus thuringiensis | Leaf Roller Larvae | As soon as larvae hatch | Recurring problems |
| Horticultural Oil | Leaf Rollers | On infested trees (follow product label) | Infested plants |
By implementing these methods, gardeners and homeowners can effectively manage leaf roller populations and protect their plants. Always follow product label instructions carefully for specific application rates and timing.
