Sawflies

Sawflies are a group insects related to wasps that get their common name from the saw-like appearance of the ovipositor, which females use to cut slits in stems or leaves to lay their eggs. The plant-feeding larvae often look like caterpillars or slugs, and many are quite noticeable because they often stay together to feed in groups and quickly cause noticeable defoliation on their hosts. Learn more about sawflies in this article…

Spotted Lanternfly

Spotted lanternfly (SLF) is an invasive planthopper native to China, India, and Vietnam. It was first detected in the U.S. in Pennsylvania in 2014, and due to its highly invasive nature, it appears to be spreading rapidly. SLF has a large host range and potentially could greatly impact the grape, tree fruit, plant nursery and timber industries in the U.S. Learn about what to watch for with this new pest.

Maple and Other Trees Disorder: Cottony Maple Scale

Author(s): C.F. Koval, D.L. Mahr, P.J. Pellitteri Cottony maple scale is an insect that can infest the twigs of maples and other shade trees with popcorn-sized cottony masses. These masses produce a considerable amount of sticky liquid that resembles tree sap and eventually turns black due to fungal growth. Infestations are usually more severe in […]

Deciduous Tree and Shrub Disorder: Skeletonizing by Rose Chafer

Author(s): R.C. Williamson, C.F. Koval Skeletonizing of the leaves of roses, raspberries, grapes, fruit trees, and many other cultivated trees and shrubs may be caused by the adult rose chafer, Macrodactylus subspinosus (Fabricius). Adult beetles are attracted to flower blossoms, particularly roses and peonies. Damage occurs in June and tends to be most severe in […]

May/June Beetles

May/June beetles or “Junebugs” (Phyllophaga spp.) are beetles in the family Scarabaeidae. These native insects are common throughout Wisconsin and can often be seen flying near lights or heard hitting window screens on early summer evenings. Learn more about these large beetles and their larva, found in the soil, in this factsheet.

Professional Guide to Emerald Ash Borer Insecticide Treatments

A variety of insecticide products and application methods are available to professionals for control of the emerald ash borer (EAB).  Since the presence and infestation level of EAB is quite difficult to determine at early stages of an infestation, insecticide treatments may be merited to mitigate damage by EAB.  However, not all ash trees should be treated as some may be too extensively compromised or in poor condition to receive treatment.

Mealybugs

Karen Delahaut, formerly UW-Madison Fresh Market Vegetable Program Revised:  4/26/2004 Item number:  XHT1129 Mealybugs are slow-moving, small, oval insects that are covered with a white, cottony wax.  They are tropical insects that are typically only found on perennial foliage plants, and rarely on flowering or bedding plants.  They can infest all plant parts including the […]

Two-Lined Chestnut Borer

Phil Pellitteri, UW Insect Diagnostic Lab Revised:  8/13/2012 Item number:  XHT1155 The most important insect cause of oak mortality is the two-lined chestnut borer (Agrilus bilineatus).  This insect is attracted to stressed and weakened oaks.  Environmental extremes (e.g., drought), construction injury to roots, soil compaction, road salt injury, defoliation by leaf-feeding insects, storm damage and […]

Cicada Killer Wasps

Phil Pellitteri, UW Insect Diagnostic Lab Revised:  1/4/2011 Item number:  XHT1198 Cicada killer wasps have become very common in the southern half of Wisconsin.  These solitary wasps are up to 1½ inches long, and their black and yellow coloring makes them look like giant yellow jackets. Life Cycle:  Adult cicada killer wasps appear from mid-July […]

Four-Lined Plant Bug

Carla Staab*, Milwaukee Area Technical College, and Phil Pellitteri, UW Insect Diagnostic Lab ompleted as partial fulfillment of the requirements for an associate degree in Horticulture at the Milwaukee Area Technical College. Revised:  4/27/2004 Item number:  XHT1101 The adult four-lined plant bug (Poecalocapsus linectus) is a 1∕2 inch long, yellowish to yellowish-green true bug with […]

Pear Slug (Pear Sawfly)

Phil Pellitteri, UW Insect Diagnostic Lab Revised:  12/30/2010 Item number:  XHT1200 Pear slugs are not true slugs (see University of Wisconsin Garden Facts XHT1040), but are larvae of the pear sawfly (Calora cerasi). These larvae feed and cause damage on many kinds of ornamentals and fruit trees, including cherry, cotoneaster, mountain-ash, pear, purple leaf plum […]

Cicadas

R. Chris Williamson, UW-Extension Turf and Ornamental Specialist Revised:  8/13/2012 Item number:  XHT1068 Adult periodical cicadas (Magicicada spp.) are black and have reddish-orange eyes and legs, and have clear wings with orange veins that are positioned over their bodies like a roof or canopy.  Male cicadas typically make a loud buzzing noise or squawk when […]

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