What's eating my pelargonium peltatum 'amethyst'?

Pelargonium peltatum 'Amethyst', an ivy-leaved trailing geranium grown in hanging baskets and containers, is most vulnerable to vine weevil grubs destroying roots and aphids on new shoots. Outdoors, caterpillars and geranium sawfly can also shred foliage, causing rapid and visible leaf damage.

Trailing stems wilt and die back; white grubs found eating the roots when basket compost is inspected. Apply Steinernema kraussei nematodes to moist compost late summer; use a preventive vine weevil compost drench at potting time.

Shoot tips distort; sticky deposits on leaves; clusters of green or greyish insects visible. Spray with insecticidal soap or dilute neem oil; repeat every 5–7 days; remove heavily infested growing tips.

Larvae skeletonise leaves from the underside, leaving a lacy, papery appearance. Inspect undersides of leaves regularly; pick off larvae by hand; spray with pyrethrum or spinosad if infestation is heavy.

Irregular holes across leaves; may find caterpillars resting on or beneath foliage. Hand-pick; apply Bacillus thuringiensis spray; check baskets at night when caterpillars are most active.