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Insect Pests

Aphids or plant lice are tiny pale green insects that appear in early spring especially on the succulent green flower buds. They increase rapidly and do their damage by sucking the sap out of whatever part of the plant they attack. Spray with Black Leaf 40: 2 tablespoons in a gallon of water applied 2 or 3 days in succession. Another remedy is aphine: 1 part aphine to 20 parts water. Spray thoroughly and on both sides of the leaves; as the insects are the same color as the plant they are hard to detect and if the spray misses a few they will soon cover the bush with their progeny as they reproduce rapidly.

Rose bugs or beetles appear suddenly in June and they are a most troublesome pest especially as no spray seems to discourage their advances. Hand picking is the only effectual means of control; every morning armed with a glass or a can half filled with kerosene go over the bushes thoroughly, picking off the beetles and dropping them in the kerosene.

Rose slugs appear first on the under side of the leaves which they eat, finally skeletonizing them. Two tablespoonfuls of white powdered hellebore in a bucket of boiling water, applied when cool with a whisk broom to the under sides of the leaves, is an efficacious remedy recommended by Mr. George C. Thomas, Jr. [133] Rose thrips affect the foliage, turning it yellow in a short time. They are small, white insects with clear wings and appear under the leaves. Spray with aphine diluted as for aphids, or whale oil soap, 1/2 pound soap dissolved in 4 gallons of water.

Rose leaf-hoppers: first appear in early June; they are small whitish insects that hop from leaf to leaf sucking the juices and causing the leaves to turn yellow. Spray with aphine or Black Leaf 40 as for aphids, or whale oil soap as directed above. Several successive sprayings are usually necessary for this pest, taking care to cover the under sides of the leaves especially carefully.

Borer: Cut away destroyed wood and burn immediately. Leaf-roller. These are small caterpillars about 1/2 inch in size and, as their name signifies, they roll themselves up in the leaves making it difficult to reach them with a spray. Dusting the plants with powdered hellebore applied while the dew is on the leaves to help it adhere discourages their advances, but hand picking is the most effectual means of control.

DISEASES Powdery Mildew. To prevent its occurrence avoid watering late in the afternoon, and during protracted [134]