Plant Diseases on a Laurus Nobilis. There are about 72 species of aphids which feed on plants in the genus Prunus worldwide.Prunus is here taken to include plum and cherry, as well as almond, apricot, cherry laurel, peach and blackthorn. Aphids are common garden pests found in just about every region of the country. - X Cupressocyparis leylandii .

Woolly Aphid Control. They are visible to the naked eye, and their colors — including green, yellow, black and red — change depending on the species of the plant being eaten. Bay laurel (Laurus nobilis) -- sometimes called sweet bay -- produces fragrant foliage used for seasoning and essential oils.

Generally, their numbers are kept low with natural predators like lacewings, ladybugs, hover flies, and parasitic wasps.

It is causing severe damage and even death to Leylandii hedges throughout the UK. The scourge of neighbours and gardeners alike is seemingly under attack - literally, from a small bug - The Cypress Aphid! A few aphids can be dealt with, but you need to be thorough or the result could be disaster for your whole garden. They feed on most plant types, and more than 4,000 species cause rapid defoliation and eventual death of the plant.

Not surprisingly aphids are the most common pest you will encounter in your hedge, there are over 500 species in the UK. What might be killing your Leylandii hedge, with large brown patches. California bay laurel (Laurus nobilis) is an evergreen that can grow up to 75 feet tall. Since severe woolly aphid attacks rarely occur, there is little need for woolly aphid pesticide for control. Aphids on plum and cherry. Many of these aphids are in the genera Brachycaudus, Hyalopterus, Thopalosiphum, Myzus and Phorodon, and have Prunus as the primary host genus.

As the aphids feed, they produce honeydew, and the sooty mold uses the honeydew as a food source. California laurel aphid is found on the undersurface of the leaves and is a small (a sixteenth of an inch diameter) ball which is gray-white.

According to the University of California Davis, it has several insect pests, including aphids, beetles, borers and scale. If you have any doubts at all treat the plant before introducing it. Leylandii hedges being killed by Aphid Attack. Aphids are sap-sucking bugs, around 3mm long, that usually infest the young soft growing tips of plants in spring and summer. Aphid eggs are tiny, but they lay them in bunches so they should be visible as small white flecks. The aphids tend to line up along the mid-vein and lateral veins of the leaf. If the plant turns out to be heavily infested it’s best to get rid of it.