CSLB C-27 Landscaping ContractorPlanting and LandscapingHard
A landscape technician observes a significant infestation of scale insects on a client's ornamental shrub. The client prefers an environmentally sensitive approach to pest control. Which of the following is the most appropriate initial treatment strategy?
- APruning and destroying infested branches, then applying horticultural oil.
- BApplying a broad-spectrum systemic insecticide.
- CReleasing parasitic wasps (biological control agents).
- DPhysically scrubbing the scales off with a soft brush and soapy water.
Show answer & explanationAnswer & explanation
Correct answer: A. Pruning and destroying infested branches, then applying horticultural oil.
For scale insects, an environmentally sensitive approach often involves cultural and mechanical controls first. Pruning heavily infested branches removes a significant portion of the population. Horticultural oil then provides effective control by suffocating remaining scales, with minimal impact on beneficial insects or the environment compared to broad-spectrum insecticides.
Why the other options are wrong
- B. Broad-spectrum systemic insecticides can harm beneficial insects and have a wider environmental impact, which goes against an 'environmentally sensitive' approach.
- C. Releasing parasitic wasps is a good biological control, but it's often a longer-term strategy and may not provide immediate knockdown for a 'significant infestation' without initial reduction.
- D. While effective for small, accessible infestations, physically scrubbing is often impractical for a 'significant infestation' on an entire ornamental shrub.
Environmentally Sensitive Scale Control
Pest management strategies for scale insects that prioritize minimal environmental impact, often involving cultural practices, mechanical removal, and targeted low-toxicity treatments like horticultural oils.
- Scale insects are sap-sucking pests often covered by a protective shell.
- Horticultural oils suffocate scales by blocking their breathing pores.
- Pruning infested parts reduces pest population.
- Avoids broad-spectrum pesticides that harm beneficial insects.
Memory trick: Scale's Secret: Prune, then oil, for a gentle foil!