How to Grow Green Beans Canada | Care, Pests & Disease Control

Uromyces appendiculatus

RHS: bean rust affects "Phaseolus (dwarf, French, runner beans etc.)". The RHS French bean guide names "Runner and French bean rust" among its diseases.

Pseudomonas syringae pv. phaseolicola

UC IPM covers halo blight on dry beans (Phaseolus vulgaris), which is the same species as French bean.

Colletotrichum lindemuthianum

Cucumber mosaic virus (CMV)

Beans, including French bean, are among the recognised host plants of cucumber mosaic virus (aphid-vectored, so control focuses on managing aphids and removing infected plants promptly rather than spraying for the…

Aphididae (various spp.)

Heavy populations stunt plants by withdrawing large volumes of sap and delaying maturity. Once the weather warms, natural enemies usually bring them under control on their own.

Gastropoda (slugs, various spp.)

RHS French bean guide lists slugs and snails among French bean pests.

Gastropoda (snails, various spp.)

RHS French bean guide lists slugs and snails among French bean pests.

Tetranychus urticae

Tiny specks on leaf undersides; lightly infested leaves show whitish speckling, heavily infested ones turn pale yellow or bronze and dry up. In hot dry weather a generation can complete in as few as eight days, which…

Elasmopalpus lignosellus

Larvae bore into the stalk near the soil line and tunnel up and down it; damaged plants become stunted, wither and die. Moths move out of field corn as it dries and into late-sown beans, so late plantings after 1 July…

Delia platura; Delia florilega

RHS: bean seed fly affects "Seedling French and runner beans". The RHS French bean guide also names bean seed fly among its pests.

Aphis fabae species group

RHS: blackfly affects "broad, French and runner beans". The RHS French bean guide also names blackfly (black bean aphid) among its pests.

Cerotoma trifurcata

Damage is twofold: stems girdled near the soil line, and large irregular holes chewed in the leaves. Early-season damage can thin the stand outright.

Helicoverpa zea

Chews holes in foliage but prefers the pods. Clemson's action threshold is 5% of pods damaged, or one larva per 3 feet of row. Mainly a problem on late plantings.

Lygus lineolaris

Withdraws sap and injects toxic saliva, which can halt development of blooms and young pods and leaves dark spots on older pods. Most important at full bloom, and late-planted beans are highly susceptible. Threshold:…

Thysanoptera

Their presence in flowers at early bloom interferes with pollination -- Clemson puts the threshold at three thrips per flower -- and the result is defectively shaped pods rather than obvious leaf damage. Aluminium foil…

Nezara viridula

Feeds on pods in preference to leaves, sucking juices and injecting toxins; snap bean pods show clear or water-soaked areas, and inside the pod the developing beans brown as the toxins and introduced yeasts take hold.…

Epilachna varivestis

Both larvae and adults feed on leaf undersides, leaving the veins and giving the leaf a skeletonized, lacy look. Egg to adult takes about a month and there are usually three generations a year, so numbers build fast.…

Soil pH range

Span reflects genuine variation between the cited authorities, not a single agreed figure.

Seedlings establish quickly once frost risk has passed. Dwarf varieties like these need no support at all; taller or heavier-cropping types benefit from a short cane to lean on once pods start to weigh the plant down.

Each flower is followed within days by a small pod forming right behind it. Flower colour varies with variety -- white, pink or purple -- but it has no bearing on the pod's eventual colour.

Purple, yellow (wax) and green pods, round or flat, are all French beans under the skin -- the same growing needs and harvest window regardless of colour. Purple pods are a useful trick for spotting ripe pods in dense foliage, though they turn green again when cooked.

Pick pods once they snap cleanly rather than bend -- a good guide that the inner beans are still small and the pod itself is still tender rather than fibrous.

Because the plant keeps flowering as long as pods are removed, a single dwarf plant can give several pickings like this over its few productive weeks -- provided none are left on the plant to mature and stop it cropping.