Got a houseplant query? Our expert is here to help. This week, how to deal with tiny, sap-sucking pests. What’s the problem?. I’ve tried everything to get rid of these pests but they just keep coming back. Diagnosis. These tiny, sap-sucking insects reproduce rapidly and often hide under leaves and within new growth. If they keep returning, it’s likely that some eggs or larvae are surviving treatments, there are hidden thrips in soil or crevices, or your approach needs a more aggressive, multi-step routine to fully eradicate them.
![[Gynelle Leon]](https://i.guim.co.uk/img/uploads/2022/02/18/Gynelle_Leon.png?width=75&dpr=1&s=none&crop=none)
Prescription. To break the cycle, you’ll need a consistent, layered attack: quarantine affected plants, trim off and immediately dispose of infested leaves. Wipe all leaves with insecticidal soap or a diluted neem oil solution every three to four days for at least a month. Thrips can lay eggs in the soil, so remove the top few inches and replace it. Place yellow sticky traps near plants to catch flying adults before they lay eggs. Thrips prefer dry conditions, so raising humidity above 70% using a humidifier can aid their demise. You can also try the radical but sometimes effective route of covering your plant with a clear bag for a week post-cleaning. Or introduce lacewing larvae or predatory mites (Amblyseius cucumeris), which target thrips at multiple life stages.
Prevention. Even once they’re gone, continue using sticky traps and wiping leaves occasionally. Quarantine new plants for at least two weeks before bringing them into your home. Got a plant dilemma? Email saturday@theguardian.com with ‘Houseplant clinic’ in the subject line.
