Gruett Tree Care

Hard Scale (Armored Scale)

carlos — Tue, 03 Jan 2012 21:45:34 +0000

Hard or Armored Scales are aphid-like insects that produce a hard waxy shell to protect themselves from predators and environmental conditions. Armored scale females resemble legless bumps and damage plants with their sucking mouthparts. The smaller male scales have wings and while in the nymph stage also feed on plants. Female scale continue to feed as they produce hundreds of eggs under each shell . The mature adult female dies, but the eggs survive the winter under the protection of the shell. In the spring and summer of the following year, the eggs hatch into an immature stage called the “crawler” stage. The crawlers, also called nymphs move out from under the shell and find a new location on which to feed. As they settle they begin to produce their hard shell. Armored scales feed primarily on the woody tissue of trees. Unlike soft scales and aphids, which feed from the circulatory system of the tree, armored scales feed on the contents of individual cells. Since they destroy cells, they can cause significant dieback of infected stem tissues and in severe infestations, even the death of trees.

Boring Insects

carlos — Tue, 03 Jan 2012 21:44:42 +0000

Many insects have the potential to devastate a single specimen of tree or a whole stands of trees. However, insects that bore into a tree to feed on living wood tissue are at the top of the list of destructive pests. Almost all trees and shrubs are able to be attacked from boring insects. Healthy trees can fend off initial attacks by forming callus tissue or by creating toxic compounds that will kill young insect larvae. Trees that are under some form of stress are more attractive to attack and are less able to respond defensively.

Most damage done by borers is caused by the larvae or immature stage of the insect. Eggs are typically laid in bark crevices, branch junctions or near open wounds. When the eggs hatch the small larvae chew their way through the bark to the point where the wood and bark meet. This section of wood contains the living nutritious tissues on which most borer larvae feed. These tissues, called xylem and phloem, serve as the trees’ transport system to move water and nutrients up from the roots to the leaves, and sugars from the leaves down to the roots.

When these tissues are damaged by borers the tree loses its ability to transport nutrients and also reduces its ability to respond to the borer. It is incredibly important to keep a trees’ vigor up to reduce both its attractiveness and it’s susceptibility to borers. In many cases, borers also carry diseases, such as Dutch Elm Disease that can infect the tissues in the tree and increase the rate of decline.

Borer Management

Unfortunately, most borer infestations go unnoticed until external signs of damage begin. Damage is not usually visible until after at least one year of infestation, when exit holes of the adult are seen in bark and when dieback occurs in the tree due to the disruption of the transport system. At this point a tree needs help to recover from the damage.

Two approaches can be taken to reduce the impact of the borer and increase the chance for the tree to overcome the situation. The first approach is to increase the vigor of the tree. This is done by identifying the stress factor(s) that contributed to the initial decline of the tree and take action to fix it. The other is the use of systemic pesticides.

Remember that here at Gruett We Speaks Tree; and based off the overall situation the tree is under we administer the best treatments possible.

Soft Scale

carlos — Tue, 03 Jan 2012 21:44:14 +0000

Soft scales are aphid-like creatures that feed on the nutrient rich sap of trees. Immature scales, called crawlers feed on leaves whereas mature scales will mainly feed on branches. Soft scales also secrete a waxy covering, but unlike armored scale it is an integral part of their body. All soft scales feed on the sap contents of the tree which means they are susceptible to systemic insecticides. They also produce a lot of honeydew that attracts ants and is necessary for the growth of sooty mold. Dormant oils and contact insecticides can be effective, but only if they are applied to the unprotected crawler stage of the scale. Thus, timing of contact insecticide application is critical to effective control.

Many species of scales are highly parasitized by tiny wasp parasites. Pin-sized holes in the wax are the only evidence of parasitism since most of these wasps are hard to see. Scale crawlers are also preyed upon by numerous beneficial insects.

Spider Mites

carlos — Tue, 03 Jan 2012 21:41:29 +0000

Mites are common pests in landscapes and gardens that feed on many fruit trees, vines, berries, vegetables, and ornamental plants. Although related to insects, mites aren’t insects but members of the arachnid class along with spiders and ticks. Spider mites, also called webspinning mites, are the most common mite pests and among the most ubiquitous of all pests in the garden and on the farm.

IDENTIFICATION

To the naked eye, spider mites look like tiny, moving dots; however, you can see them easily with a 10X hand lens. Spider mites live in colonies, mostly on the undersurfaces of leaves; a single colony may contain hundreds of individuals. The presence of webbing is an easy way to distinguish them from all other types of mites and small insects such as aphids and thrips, which can also infest leaf undersides.

Adult mites have eight legs and an oval body with two red eyespots near the head end. Females usually have a large, dark blotch on each side of the body and numerous bristles covering the legs and body. Immature mites resemble adults (except they are much smaller), and the newly hatched larvae have only six legs. The other immature stages have eight legs. Eggs are spherical and translucent, like tiny droplets, becoming cream colored before hatching.

LIFE CYCLE

In some parts of California, spider mites may feed and reproduce all year on plants that retain their green leaves throughout the winter. In colder areas and on deciduous trees that drop their leaves, webspinning mites overwinter as red or orange mated females under rough bark scales and in ground litter and trash. They begin feeding and laying eggs when warm weather returns in spring.

Spider mites reproduce rapidly in hot weather and commonly become numerous in June through September. If the temperature and food supplies are favorable, a generation can be completed in less than a week. Spider mites prefer hot, dusty conditions and usually are first found on trees or plants adjacent to dusty roadways or at margins of gardens. Plants under water stress also are highly susceptible. As foliage quality declines on heavily infested plants, female mites catch wind currents and disperse to other plants. High mite populations may undergo a rapid decline in late summer when predators overtake them, host plant conditions become unfavorable, and the weather turns cooler as well as following rain.

DAMAGE

Mites cause damage by sucking cell contents from leaves. A small number of mites usually isn’t reason for concern, but very high populations can damage plants, especially herbaceous ones. At first, the damage shows up as a stippling of light dots on the leaves; sometimes the leaves take on a bronze color. As feeding continues, the leaves turn yellowish or reddish and drop off. Often, large amounts of webbing cover leaves, twigs, and fruit. Damage is usually worse when compounded by water stress.

Spider mites have many natural enemies that often limit populations. Adequate irrigation is important, because water-stressed plants are most likely to be damaged. Broad-spectrum insecticide treatments for other pests frequently cause mite outbreaks, so avoid these pesticides when possible.

Aphids

carlos — Tue, 03 Jan 2012 19:04:31 +0000

Aphids (Aphidoidea) feed on the sap tissue using a proboscis. They produce enormous amounts of honeydew as their waste. Honeydew produces a sticky film on and underneath infested trees. Due to their feeding on sap tissue, they are easily controlled by systemic insecticides. Aphids do not need to mate, and are essentially born pregnant. Because of this, they can build into huge populations over a relatively short period of time.

Damage

Aphids will suck out the sap from leafs, branches or any part of the tree where their mouth will be able to penetrate to the phloem (part of plant that moves nutrients). They will excrete ‘Honeydew’, which are clear viscous drops that will leave a medium for sooty mold to grow on and for other insects to eat. The leaves of some plants will be stunted, shriveled, or curled as a result of high populations. Many species are green, but may be white, yellow, brown, red, black, or mottled

Aphid Predators

There are wasps’ worms and lady bugs that are all predators of aphids and other harmful insects. The natural predators are successful in controlling and preventing outbreaks, but just like their prey they are susceptible to pesticides. In most cases it is better to allow for the natural pests to control the infestation.

If you’re unsure about what form of pest control to use contact Gruett.

Redgum Lerp Psyllid

carlos — Wed, 04 Jan 2012 07:29:21 +0000

The redgum lerp psyllid (Glycaspis brimblecombei) was originally from Australia. It was found in Los Angeles in 1998 and has spread throughout much of California since then. It also occurs in Arizona, Florida, Hawaii, and Mexico on a variety of eucalyptus.

IDENTIFICATION

Psyllids are plant-juice sucking insect in the insect family Psyllidae. Redgum lerp psyllid nymphs form a cover called a “lerp,” which is a small white, hemispherical cap composed of solidified honeydew and wax. Lerps on leaves can be up to about 1/8 inch in diameter and 1/12 inch tall and resemble an armored scale. Nymphs enlarge their lerp as they grow, or they move and form a new covering. The yellow or brownish nymphs resemble a wingless aphid, and spend most of their time covered beneath a lerp.

Adults are about 1/8 inch long, slender, and light green to brownish with orangish and yellow blotches. Adults occur openly on foliage and do not live under lerp covers. Females lay tiny, yellowish, ovoid eggs singly or in scattered groups.

Females prefer to lay eggs on succulent leaves and young shoots. Population increases often coincide with new plant growth. However, all psyllid life stages can occur on both new and mature foliage. Development time from egg to adult varies from several weeks during warm weather to several months during prolonged cool temperatures. This insect has several generations each year. All stages can be present throughout the year, although in lower numbers during the winter.

Damage

Psyllid nymphs and adults feed by sucking plant phloem sap through their strawlike mouthparts. High redgum lerp psyllid populations secrete copious honeydew and cause premature leaf drop. Sticky honeydew droppings, the resulting dark sooty mold growth, and falling leaves will foul the surfaces beneath infested trees and make the tree more attractive to pests. In some cases the large amounts of honeydew will attract yellowjackets that may annoy or threaten people. Extensive defoliation weakens trees and contributes to premature death of some highly susceptible species.

MANAGEMENT

The species of eucalyptus primarily determines whether psyllids will be abundant. Cultural practices and overall tree health also influence populations and the extent to which trees are damaged. Providing adequate irrigation and limiting nitrogen can reduce susceptibility to damage. An introduced, psyllid-specific parasitic wasp is providing substantial biological control on coastal area trees. Systemic insecticides have sometimes provided control, but efficacy has been variable and sometimes disappointing.

If you think you have an infestation on your eucalyptus contact Gruett today!!!

Avocado Lace Bug

carlos — Wed, 04 Jan 2012 06:52:19 +0000

The avocado lace bug, Pseudacysta perseae, occurs in the Caribbean, French Guyana, Mexico, and southeastern United States. As of 2006 it only appears in San Diego County. This bug is also known as the camphor lace bug, because it feeds on certain plants in the family Lauraceae. Hosts are the avocado fruit tree, other Persea species such as red bay (P. borbonia), and camphor trees.

IDENTIFICATION

Adult lace bugs have an elaborately sculptured thorax and forewings that form an expanded cover over their body. The adult thorax and forewings have tiny clear cells that form a lacelike covering, hence the name “lace bugs.” Adults are about 1/12 inch (2 mm) long, oval-shaped insects with a dark (black or brownish) head and thorax. Their abdomen, antennae, legs, and wing covers have both dark and light (brown, orangish, or white) areas.

Eggs will be found on the lower leaf surface, covered with black, sticky excrement. To the naked eye, eggs may resemble grains of black pepper. Beneath the excrement, eggs are oblong, yellowish, and have a white rim around the cap from which nymphs will later emerge. The nymphs are mostly black or dark brown with elaborate spiny projections, pale appendages, and (on the back of older nymphs) pale areas where wings are developing.

DAMAGE

Lace bugs do not feed on fruit. They suck leaf sap, feeding in groups on the underside of leaves. A colony of lace bugs feeding causes faint pale green to yellowish blotches visible on both the lower and upper leaf surfaces. Black, shiny specks of excrement appear on the under leaf surface where lace bugs occur. As lace bugs continue feeding, large brown or tan dead blotches develop on leaves. Heavily damaged leaves become dry, may curl, and drop prematurely.

Low lace bug populations do not damage trees. Severe leaf damage results in sunburned limbs and fruit when leaves fall from trees. Tree stress from defoliation reduces subsequent fruit yields. Severe lace bug damage has not been a reported problem on camphor trees.

What should I do?

Tolerate low populations of lace bugs, which are harmless to trees and provide food for predaceous insects that may help to prevent pest outbreaks. The best defense is to keep trees healthy, by providing good soil drainage, maintaining a thick layer of organic mulch beneath the trees canopies, and watering deeply and consistently. Remember that we want to conserve natural enemies by choosing the appropriate control.

If you what to know more contact Gruett today!!!

Diaprepes Root Weevil

carlos — Sat, 31 Dec 2011 11:49:17 +0000

The Diaprepes root weevil, Diaprepes abbreviatus (L.), is a large, colorful weevil, 3/8 to 3/4 inch (10 to 19 mm) long, with numerous forms, or morphs, ranging from gray to yellow to orange and black. Because of its broad host range, the Diaprepes root weevil poses a great threat to the citrus, avocado, ornamental, and other agricultural industries in California.

ORIGIN

This weevil is native to the Caribbean region and was accidentally introduced into Florida in the 1960’s where it has caused extensive damage. It has been intercepted in shipments of plants to California and in 2005 two isolated populations were found in Newport Beach (Orange County) and Long Beach (Los Angeles County).

HOST PLANTS

This weevil will feed on about 270 different plants including citrus (all varieties), hibiscus, palm, birch, roses, coral trees, indian hawthorne, loquat, holly, and other ornamentals. Because of its broad host range, the Diaprepes root weevil poses a great threat to the citrus, avocado, ornamental, and other agricultural Industries in California.

FEEDING

The Diaprepes root weevil damages both the leaves and the roots of plants. The adult weevils damage leaves by chewing semi-circular areas out of the leaf margin. There may also be frass or weevil droppings near the areas that have been fed upon. The grub-like larva feeds upon the roots of a plant weakening or killing a plant.

LIFE CYCLE

In leaves that are folded and glued together, an adult female weevil lays clusters of eggs .04 inch (1mm) long. The eggs hatch in 7-10 days, and the newly emerged larvae drop to the soil. The larvae enter the soil and feed upon the roots of plants for several months. Full grown larvae are C-shaped and whitish, and can reach 1 inch (25mm) in length. The larvae then pupate in the soil. After the appropriate amount of time, adults will emerge and the life cycle begins again.

QUARANTINE AREAS

Since the initial finds the weevil has been found in additional areas in Southern California. To control this pest and prevent it from spreading the California Department of Food and Agriculture has established quarantine zones in the areas of Los Angeles County, Orange County, and San Diego County.

Longhorned Borer Beetles

carlos — Sat, 31 Dec 2011 11:10:00 +0000

Two closely related species of longhorned borer beetles are known to attack eucalyptus trees in California.

Phoracantha semipunctata, is native to Australia, was introduced into Southern California in the 1980s. It rapidly became a pest and now appears throughout the state wherever eucalyptus trees grow. Natural enemies were introduced from Australia, and biological control combined with improved cultural care of eucalyptus have dramatically reduced the number of trees this borer kills each year.

In 1995, a second species, Phoracantha recurva, was discovered in Southern California in Los Angeles, Riverside, Orange, and San Bernardino counties. This beetle has spread throughout much of California wherever eucalyptus grows. However, biological control has been less effective against this new borer. P. recurva, along with several other new pests, can stress and kill eucalyptus.

Freshly cut wood, dying limbs, and trees suffering from stress, especially drought stress, attract both of these beetles. Many eucalyptus trees in California grow in unmanaged or minimally managed environments with no irrigation. Eucalyptus species that grow in wetter areas of Australia have been planted in California, so when they experience prolonged dry periods, these species are especially susceptible to being attacked and killed by borers.

IDENTIFICATION AND LIFE CYCLE

Adults of the two Phoracantha species resemble each other. Their antennae are as long as or longer than their body, and the antennae of the males have prominent spines. They differ, however, in the number of hairs on their antennae and their wing color. For example, dark brown predominates on the wing covers of P. semipunctata, while yellow to cream color predominates on wing covers of P. recurva.

Several nights after emerging from infested wood and mating, the female beetles begin laying eggs in groups of 3 to 30 beneath the loose bark or in crevices on bark surfaces of eucalyptus trees. Females can live 1 or more months and lay up to 300 eggs, which hatch in about 1 to 2 weeks depending on temperature. After hatching, larvae bore directly into the inner bark, or they feed temporarily on the bark surface before boring in. If feeding on the surface, outward from the egg mass they leave a distinct, dark trail 1/4 inch to several inches long that scores the bark surface. Most larval feeding occurs in the cambium, the thin layer of tissue on the bark’s inner surface. There larvae bore galleries that can extend several feet. In trees with heavy infestations, the scraping sounds the developing larvae make while chewing in the cambium are audible from a distance of several feet.

At the end of the feeding period, larvae excavate pupal chambers in the wood. They enter the chambers, packing the holes behind them with frass (excrement) and wood shavings. Larvae require about 70 days to develop in fresh wood or logs during hot summer months and up to 180 days in drier logs. Only relatively fresh logs sustain beetle larvae; old, dry logs are too hard for larvae to feed on and then successfully develop. Mature larvae can be more than 1 inch long and are cream colored and legless.

Following pupation, adult beetles emerge from the same holes by chewing through the frass plugs. During spring and summer, the beetle requires 3 to 4 months to complete its life cycle, but starting in fall and winter it can require up to 9 months. There are two and possibly three overlapping generations a year. Larvae can be present anytime during the year, and adults can emerge from pupae anytime from April through October.

The life cycle of P. recurva differs somewhat from that of P. semipunctata. P. recurva develops more quickly and completes a generation in a shorter period of time. P. recurva adults can be present for a longer period during the year and emerge as early as February.

DAMAGE

Holes in the bark and stains or oozing liquid on limbs or trunks are common symptoms of longhorned borer damage. Foliage can discolor and wilt, and limbs can die back. Longhorned borers usually attack stressed or damaged plants, leaving vigorous, appropriately watered trees alone. In California, however, many eucalyptus trees are seasonally water stressed during hot summer months, rendering a significant proportion of them susceptible to beetle attack. Tree species with some resistance to these wood borers can produce copious amounts of resin in response to an attack.

Extensive larval feeding beneath the bark can spread around the entire circumference of a tree, girdling, or completely removing a strip of bark from, the trunk. Trees at this stage of infestation have a thin canopy with wilted or dry leaves, and the bark is cracked and packed with larval excrement. Infested trees usually die within of a few weeks of girdling, although resprouting can occur from the tree base.

Citrus leafminer

carlos — Sat, 31 Dec 2011 10:16:29 +0000

Citrus leafminer larvae feed by creating shallow tunnels, or mines, in young leaves of citrus trees. The pest is most commonly found on citrus (oranges, mandarins, lemons, limes, grapefruit, and other varieties) and closely related plants (kumquat and calamondin). The citrus leafminer is the only mining insect that commonly attacks citrus leaves. Citrus leafminer, Phyllocnistis citrella, was not found in California until 2000 when it was first detected in Imperial County. It soon spread to adjacent counties and continued to move northward. Citrus leafminer now infests most of southern California, the coast as far north as San Luis Obispo County, and the San Joaquin Valley. The citrus leafminer is native to Asia.

IDENTIFICATION

Citrus leafminer is a very small, light-colored moth, less than 1/4 inch long. It has silvery and white iridescent forewings with brown and white markings and a distinct black spot on each wing tip. The hind wings and body are white, with long fringe scales extending from the hindwing margins. The larval stage is found only inside mines of citrus leaves and other closely related plants. As it feeds and develops, the larva leaves a frass (feces) trail, observed as a thin dark line, inside the meandering serpentine mine just under the surface of the leaf. This visual characteristic is used to help identify the pest. In its last stage the larva emerges from the mine and moves to the edge of the leaf. It rolls the leaf around itself and pupates in preparation for adulthood, creating a rolled and distorted leaf. The entire life cycle of the insect takes 3 to 7 weeks to complete. Citrus leafminer develops best at temperatures between 70º to 85ºF and greater than 60% relative humidity, but will readily adapt to most California conditions.

DAMAGE

Citrus leafminer can survive as a larva only in the tender, young, shiny leaf flush of citrus and closely related species. Older leaves that have hardened off are not susceptible unless extremely high populations are present. The larvae mine inside the lower or upper surface of newly emerging leaves, causing them to curl and look distorted. Mature trees (more than 4 years old) that have a dense canopy of older foliage to sustain them can tolerate damage on new leaves during part of the growing season with negligible effect on tree growth and fruit yield. Very young trees do not have much mature foliage and they produce more flush year-round, thereby supporting larger citrus leafminer populations. Young trees may experience a reduction in growth. However, even young trees with heavy leafminer populations are unlikely to die. Summer heat in the inland areas of California seems to suppress leafminer populations, but in cooler coastal areas, the insect population may remain high from summer through fall. The flush growth of citrus trees attacked by leafminer will look unsightly, but the best course of action is to leave it alone and let the natural enemies of the citrus leafminer feed on and parasitize the larvae in the mines, rather than trying to control this pest with insecticides.

In other areas of the world where the citrus leafminer invasion is long established the experience has been similar: a high level of damage to citrus in the first year or two is followed by decreasing severity due to natural enemies parasitizing or consuming leafminers. These natural enemies, which are already present in the environment, survive by seeking out mining insects in which to lay their eggs. Eventually, the leafminer populations decline as the population of natural enemies increases.