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Conifers/leyland cypress treatment


leyland cypress trees have spittle bugs and  branches turned brown needles falling. last 3 yrs I treated them  but it keeps coming back and i want to know what kind of treatment and if insecticidal soap to the roots will help.I SPRAYED WITH CLEAR WATER .WILL THEY DIE?

Spittlebug do not kill branches of Leyland cypress. The white frothy spots on your leyland are spittle bugs. A nymph is encrusted in plant juices for protection. Even when numerous on leylands they are often not a problem and are temporary.  A hard spray of water may dislodge them.  If desired orthene or diazinon can be used.

The adult spittlebug is a large (one-half inch long) leafhopper-like insect, brownish-gray in color. The nymphs are a creamy white insect, which feeds on cypress and other hosts. The nymph protects itself by secreting a foamy, white mass of “spittle” around itself. If you carefully wash off the foam, you will find one or two nymphs under each mass of spittle. These insects do little damage to their host. The spittle can be annoying, especially if it is present on twigs where persons and pets can get into it. In such locations, a forceful stream of water from a hose can be used to wash the spittle and the nymphs off the tree.

If the branches are dying I would check for either spider mites or a disease.

Spruce Spider Mite: Mites are not insects but are more closely related to spiders. Spruce spider mites (Oligonychus ununguis) are occasional pests of Leyland cypress. They are very small and not seen easily with the naked eye. They have piercing mouthparts that they use to suck plant sap. Their feeding results in speckling (formation of tiny yellow spots) on needles. Some needles may turn brown and drop off. With heavy infestations, fine webbing may be seen on the plant. Several seasons of heavy mite feeding may kill a Leyland cypress. Although most spider mites increase in numbers during hot, dry weather, spruce spider mites are cool-weather mites. Their populations peak during spring and fall, but drop dramatically during the heat of summer when predators feed on them.

To determine whether insecticide use is needed, it helps to know how many mites are present. Hold a white sheet of paper under a branch and strike the branch. The mites that are knocked off will be seen crawling around on the paper. If dozens of mites are seen per whack, serious damage can result. Continue to check population numbers at 7- to 10- day intervals. Pesticides labeled for homeowner use against spruce spider mite include insecticidal soaps and acephate + fenbutin oxide (Ortho Systemic Insect Killer or Ortho Orthenex Garden Insect & Disease Control Concentrate). Completely cover the foliage with the spray. As with any pesticide, read and follow all label directions and precautions before using.

Seiridium canker is probably the most important and destructive disease on Leyland cypress in the landscape. Although the fungi Seiridium cardinale, Seiridium unicorne, and Seiridium cupressi have been reported to cause disease on Leyland cypress and other needled evergreens, only Seiridium unicorne is most commonly associated with cankers and twig dieback on Leyland cypress.

One of the most noticeable symptoms of Seiridium canker is yellowing or browning of the foliage on one or more top or lateral branches. The discoloration is most likely to appear in early spring; however, it can be seen at any time of the year. The disease expansion often continues until a significant portion of the tree is destroyed. Upon closer examination, formation of numerous thin, elongated cankers is observed on stems, branches and branch axils. These cankers cause twig and branch dieback. Most of the cankers are slightly sunken, with raised margins, and they may be discolored dark brown to purple. Cracked bark in infected areas is often accompanied by extensive resin exudates that flow down the diseased branches. The cambial tissue beneath oozing sites is discolored with a reddish to brown color.

To minimize water loss and water competition with other plant species such as turf, mulch an area several feet beyond the lowest limbs. During hot, dry summer days, irrigate trees thoroughly around the base of the tree every 7-14 days, depending on soil composition. Take special care for trees located near drive-ways, paved areas or heat-reflecting buildings. Providing adequate irrigation during periods of drought is the best defense against Seiridium canker disease. Do not over water.

Sanitation, such as removal of cankered twigs and branches, helps prevent disease spread. Destroy pruned materials, and disinfect pruning tools by rinsing in rubbing alcohol or a solution of 1 part bleach to 9 parts water. Remove extensively damaged trees or trees that are damaged in the main trunk.


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Jim Hyland


Registered Forester in the Southern US with 30 years experiance in managing pines. Expert in pine forest health from management to control of pests to ID of species.

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