The Situation: The Asian Woolly Hackberry aphid Shivaphis celtiwas first detected in North America on native hackberry trees ( Celtis occidentalis) in Georgia in 1996 and has been subsequently found throughout the southeastern states. In 2002 the aphid was detected in several counties in the San Joaquin Valley of California on the commonly planted Chinese...

The Situation: Eucalyptus is a ubiquitous landscape, shade, and windbreak tree throughout southern and central California. The trees are valued for their fast growth and tolerance of poor soils and drought. Eucalyptus is now threatened by several pest insects accidentally introduced into California from Australia, one of which is the Australian gum tree weevil. Description...

The Situation: Avocado lace bug, Pseudacysta perseae, was first described in Florida in 1908 from specimens collected in this state over the period 1897-1907. Avocado lace bug is a true bug with sucking mouth parts. The common name “lace bug”, is derived from the highly reticulate “lace-like-patterning” of the thorax and wings of adults. There...

The Situation: Avocados are subtropical perennial fruit trees 6-10 meters in height. California produces 95% of the nation’s crop, and 85% of this harvest is from one cultivar, the black fruit Hass avocado. Annually, 6,000 growers in California produce 260 million pounds of fruit on 65,000 acres, and the harvest in 2007 was worth $245...

The Situation: In California, black scale is a periodic pest of citrus in southern California and a consistent pest of olives in the San Joaquin Valley. It was introduced into the United States and California sometime before 1880. It now occurs in many regions of the world and infests a wide range of plants. It...

The Situation: The brown citrus aphid (BrCA), is an insect pest of all citrus varieties. It is not a pest of non-citrus crops. The brown citrus aphid infests the stems and new leaves of citrus trees and in addition to feeding damage, it is a highly efficient vector of citrus tristeza virus (CTV). CTV can...

The Situation: California red scale was introduced into California between 1868 and 1875, apparently on citrus seedlings from Australia. The scale insect is native to Southeast Asia but has been transported on citrus seedlings to all arid and semiarid regions of the world where citrus is grown. It occurs in all of California’s citrus growing...

The Situation: In California, citricola scale is a serious pest . This pest is a particular nuisance in the San Joaquin Valley when broad-spectrum pesticide use is reduced as these insecticides typically keep this pest under good control. It was also a serious pest in the inland areas of southern California until 1935, when Metaphycus...

The Situation: Citrus huanglongbing (HLB), previously called citrus greening disease, is one of the most destructive diseases of citrus worldwide. Originally thought to be caused by a virus, it is now known to be caused by unculturable phloem-limited bacteria. There are three forms of greening that have been described. The African form produces symptoms only...

The Situation: Diaprepes root weevil is a large (3/8-3/4 inch long) colorful weevil with color forms that range from gray to yellow to orange and black. Diaprepes is originally from the Caribbean and was introduced into Florida in the 1960s. The larval stage feeds on roots and causes serious damage to ornamentals, citrus and a...

The Situation: Elms are a common shade tree planted throughout the U.S. and are valued for their large, high canopies and the shade they provide. The elm leaf beetle was accidentally introduced into the U.S. in the 1830s and is now one of the most important urban forest pests in California. Damage and Economic Impact:Both...

The Situation: Approximately 90 of the more than 700 species in the tree genus Eucalyptushave been introduced into North America over the last 150 years. Eucalyptusspp. are native to Australia and New Guinea. Many residents of California find the growth form, evergreen foliage, floral show, and other horticultural qualities such as drought tolerance highly desirable...

The Situation: In southern California, the most widespread yellowjacket has historically been the native, western yellowjacket, Vespula pensylvanica. The German yellowjacket, V. germanica, became established in the Northeastern U.S. in the 1970s and then the Pacific Northwest in the 1980s where it spread down the coast. It reached southern California in 1991 becoming part of...

The Situation: Persea mite, Oligonychus perseae, was first described in 1975 from specimens collected from avocado foliage intercepted from Mexico at an El Paso, Texas, quarantine facility. Persea mite is native to Mexico and damages avocados in arid regions, a pest in the state of Michoacan where Hass avocado production is greatest. Persea mite has...

The Situation: Asiatic citrus canker is a widespread bacterial disease in Asia and in certain other citrus-growing regions of the world. It was eradicated from the U.S. after its introduction in the early part of this century. New infestations of true Asiatic citrus canker have been recently detected in Florida, suggesting that the introduction of...

The Situation: In southern California, Klambothrips myopori Myoporum, a plant genus native to Australia and New Zealand. This thrips causes considerable leaf deformation through the feeding activity of larvae and adults. This pest is likely native to Australia or New Zealand where it is probably a specialist on members of Myoporum. Damage: The plant species...

The Situation: Several species of brightly colored, ground dwelling bugs are familiar to California residents who observe the insects running over dry ground, feeding and migrating among urban vacant lots and weedy fields. Most familiar are those species with contrasting red and black coloration which feed upon developing or mature seeds and seed pods. The...

The Situation: The potato psyllid is a major insect pest of solanaceous crops growing in Central and North America. Potato psyllid has historically been a sporadic pest in California, generally developing damaging populations for 6 months or a year and then disappearing for 20 or 30 years. However, since the year 2000, year-round populations have...

The Situation: Phytophthora ramorum is one of several species of related fungus-like water molds (oomycetes) that are pathogenic to plants. Another member of this group, P. infestans, is notable as the cause of the potato blight epidemics in Europe in the mid-1800s. More recently, P. ramorum has emerged as a major threat to California woodlands...

The Situation: Upwards of 40% of amphibian species are in decline worldwide, owing to several factors such as habitat loss, environmental degradation, pollutants, and disease. Recently the fungal pathogen Batrachochytrium dendrobatidis has emerged as a major threat to amphibians. Amphibians infected with B. dendrobatidis develop chytridiomycosis, which eventually causes death in susceptible species. The first...