Pest identification
What's eating my yardlong bean?
Cowpea aphid (Aphis craccivora)
Signs: Dense black colonies on shoot tips and young pods; honeydew causes sooty mould and slows growth.
Control: Knock off with a strong water spray. Apply insecticidal soap or neem oil. Attract natural enemies with companion flowers. Remove heavily infested tip growth.
Bean thrips / chilli thrips (Scirtothrips dorsalis and Caliothrips fasciatus)
Signs: Silvery scarring on pods and leaves; buds may fail to open; pods look mottled and lose market value.
Control: Spinosad or insecticidal soap applied early morning. Blue sticky traps to monitor populations. Avoid dusty conditions that favor thrips. Reflective mulch deters adults.
Bean fly / bean stem maggot (Ophiomyia phaseoli)
Signs: Yellowing and wilting of seedlings; stem base shows maggot tunnels; plant may collapse at soil level.
Control: Use row covers or fleece tunnels for first 3–4 weeks. Start transplants indoors. Remove and destroy wilted seedlings. Crop rotation limits soil-dwelling pupae.
Brown marmorated stink bug (Halyomorpha halys)
Signs: Feeding punctures on pods cause dimpled, cat-faced deformity; seeds inside are shriveled.
Control: Hand-pick adults (use gloves; crush off-site). Kaolin clay applied to pods deters feeding. Row covers before pod set. Beneficial parasitic wasps (Trissolcus japonicus) where established.
Keep yardlong bean pest-free
Healthy plants resist pests best. Get the basics right:
Yardlong Bean pests — FAQ
What is eating my yardlong bean?
Yardlong beans in the garden are bothered by aphids on tender tips, thrips that silver leaves and pods, bean flies whose larvae mine stems, and stink bugs that deform developing pods. In warm US climates Japanese beetle also feeds. Consistent scouting and row covers at establishment give the best protection.
How do I get rid of cowpea aphid (aphis craccivora) on yardlong bean?
Dense black colonies on shoot tips and young pods; honeydew causes sooty mould and slows growth. Knock off with a strong water spray. Apply insecticidal soap or neem oil. Attract natural enemies with companion flowers. Remove heavily infested tip growth.
How do I get rid of bean thrips / chilli thrips (scirtothrips dorsalis and caliothrips fasciatus) on yardlong bean?
Silvery scarring on pods and leaves; buds may fail to open; pods look mottled and lose market value. Spinosad or insecticidal soap applied early morning. Blue sticky traps to monitor populations. Avoid dusty conditions that favor thrips. Reflective mulch deters adults.
How do I get rid of bean fly / bean stem maggot (ophiomyia phaseoli) on yardlong bean?
Yellowing and wilting of seedlings; stem base shows maggot tunnels; plant may collapse at soil level. Use row covers or fleece tunnels for first 3–4 weeks. Start transplants indoors. Remove and destroy wilted seedlings. Crop rotation limits soil-dwelling pupae.
How do I get rid of brown marmorated stink bug (halyomorpha halys) on yardlong bean?
Feeding punctures on pods cause dimpled, cat-faced deformity; seeds inside are shriveled. Hand-pick adults (use gloves; crush off-site). Kaolin clay applied to pods deters feeding. Row covers before pod set. Beneficial parasitic wasps (Trissolcus japonicus) where established.