These Insects Prey on Toadflax

1 4 2 These insects prey 3 5 6 on Toadflax 1. Brachypterolus pulicarius 2. Calophasia lunula 3. Eteobalea serratella 4. Gymnetron antirrhini 5. Gymnetron linariae 6. Mecinus janthinus Some are beneficial . biological noxious weed control can be elusive and long term The flower-feeding beetle Brachypterolus Seed capsule and root-galling weevils density and cases of multiple pulicarius was brought to North America by Gymnetron antirrhini and G. linariae were attacks. Effects of the weevil accident in 1919, probably in a shipment of released in Montana from Eurasia in 1996. on the plant reportedly are toadflax. The beetle adult eats the tips of The Dalmatian toadflax-adapted strain of G. enhanced under drought stress. toadflax shoots, and the larvae feed on antirrhini was first released in Montana in A small release of the Dalmatian pollen, flower parts, and seeds. Feeding on 1996. The yellow toadflax strain is estab- toadflax-adapted strain of yellow toadflax can reduce the number of lished in Idaho, Montana, Oregon, Gymnetron linariae occurred seeds by 80 to 90%. Although seed reduction Washington, and Wyoming. These insects are in Wyoming in 1998. As of is huge, scientists consider this ineffective generally available where yellow toadflax 2003, this was the only because it does not reduce plant populations. infestations occur. The only definitive record definitive record of G. Two root-boring moths Eteobalea interme- of Gymnetron linariae establishment in the linariae establishment diella and E. serratella lay their eggs on United States is at a solitary Dalmatian in the United States. toadflax, and their larvae then feed on the toadflax site in Wyoming. A small release of root crown. This really damages the roots and the Dalmatian toadflax-adapted strain weakens the whole plant. As the plant dies occurred in Wyoming in 1998. off, the top of the root easily breaks off, and Mecinus janthinus, toadflax stem weevil, the plant can’t grow any more. The toadflax was first introduced into Montana in 1996 moth Calophasia lunula lays its eggs on and is established in Colorado, Idaho, toadflax. The eggs hatch within 11 days, and Montana, Washington, and Oregon. Adult Dalmatian Toadflax the little gray-black larvae start feeding on the stem weevils attack both Dalmatian and Linaria dalamatica plant’s leaves and flowers. The larvae grow yellow toadflax leaves and stems. Larvae into inch-long caterpillars with black and mine the stems. In Europe, adult feeding on bright yellow stripes running the length of the leaves and stems apparently has a limited their bodies. If enough caterpillars feed on a effect under field conditions. However, mining Statewide Noxious Weed Awareness and Education Campaign stand of toadflax, they can strip off most of of the stems by the larvae causes premature the leaves and flowers. This weakens the wilting of shoots and suppresses flower Montana State University Land Resources and Environmental Sciences plants and reduces the number of seeds formation, particularly under in cooperation with produced. conditions of high weevil United States Department of Agriculture Animal and Plant Health Inspection Service Plant Protection Quarantine This insect preys on Saltcedar Diorhabda elongata Some are beneficial . biological noxious weed control agents Most weed plants are weed-size, not That kind of thirst reduces streams to a tree-size. One of the largest noxious weeds in trickle, or even drinks them dry. Saltcedar the United States is saltcedar, a shrub or tree clogs river channels and reduces the size of that can grow to be thirty feet tall. Imagine a spring floods. Floods are part of the natural weed as tall as a three-story house! ebb and flow of many rivers, and many Scientists are experimenting with an insect native plants depend on floods. Cottonwood that eats saltcedar, called the saltcedar leaf trees and willows, for example, will grow beetle Diorhabda elongata. The saltcedar leaf only where floods scour mud off the gravel beetles were brought to the United States in and cobblestones. 2001 from Asia, just like the saltcedar. An Once saltcedar takes over an area, it adult beetle lays up to 200 eggs on a keeps other plants out by oozing salt from saltcedar plant. When they hatch, the larvae its leaves. The leaves dip and fall to the eat the leaves. Together, adult beetles and ground, making the surrounding soil too larvae can strip all the leaves off a saltcedar salty for most plants. Soon, birds, animals, plant. When a swarm of beetles eats a stand and even insects are driven away to look of saltcedar bare, they’ll fly a few hundred elsewhere for food. yards to the next saltcedar dining table. Saltcedar grows along streams and rivers, around springs, and along the shores of lakes and reservoirs. A stand of saltcedar can suck Saltcedar the ground dry, using 200 or more gallons of Tamarix ramosissima water every day. That’s enough in a growing season to create a swimming pool the size of Statewide Noxious Weed Awareness a city block and 9 feet deep! and Education Campaign Montana State University Land Resources and Environmental Sciences in cooperation with United States Department of Agriculture Animal and Plant Health Inspection Service Plant Protection Quarantine 1 2 These insects prey on 4 3 Purple Loosestrife 1. Galerucella calmariensis 2. Galerucella pusilla 3. Nanophyes marmoratus 4. Hylobius transversovittatus Some are beneficial . biological noxious weed control agents are host specific Researchers study insects that feed on Why is it not bad when these insects also feeds on two native particular plants. Plants that insects feed on damage purple loosestrife? plants, Swamp loosestrife exclusively are called the insect’s “host” plant. Decodon verticillatus and Purple loosestrife, once established, For example, purple loosestrife is a host plant Winged loosestrife Lythrum changes how riparian systems function. These for loosestrife beetles. The black-margined alatum, and two introduced insects were introduced to control purple and golden purple loosestrife beetles, plants, Lesser loosestrife loosestrife spread. Researchers introduced Galerucella calmariensis and G. pusilla were Lythrum hyssopifolia and these insects because they attack purple introduced into the United States from the tree Crape Myrtle loosestrife without significant impacts on other northern Germany in 1992. More golden Lagerstroemia indica. plants or endangered species. A lot of testing beetles were released than its look-alike and The black-margined and research goes into selecting biological highly mobile black-margined beetle. The beetle was permitted control agents. A technical advisory group adult black-margined beetle feeds on because it does not (TAG) helps with communications between loosestrife leaves and buds while the golden reproduce on these groups responsible for environnmental and beetle skeletonizes and defoliates loosestrife host plants. potential risk to endangered species. so severely that the plant turns brown. Once the public have an opportunity to Hylobius transversovittatus root weevils comment and the responsible regulatory deplete loosestrife root storage reserves agencies have together found no significant during the growing season and and impact on anything besides the target plant, Nanophyes mamoratus seed weevils tolerate in this case purple loosestrife, a permit is a wide range of climates and landscapes issued and insects can be placed in quaran- Purple Loosestrife where they easily find purple loosestrife. Lythrum salicaria tine. Quarantine laboratories confirm insect Depleted root storage reserves limit looses- identity, get rid of parasites, and check for trife’s ability to recuperate after the beetles and eliminate diseases before insects insects Statewide Noxious Weed Awareness defoliate the leaves. Although more damage are released into the field. and Education Campaign is done by the other insects, scientists believe Although purple loosestrife is the Montana State University the seed weevil may play an important role Land Resources and Environmental Sciences after loosestrife abundance declines and other targeted plant, the black- in cooperation with insects become less effective. margined loosestrife beetle United States Department of Agriculture Animal and Plant Health Inspection Service Plant Protection Quarantine This pathogen feeds on Yellow Starthistle Puccinia jaceae Some are beneficial . biological noxious weed control insects and pathogens Some biological control agents are not While scientists learn more about fungus, insects, they are plant pathogens. Pathogens weevils with well-developed snouts and such as bacteria, fungus, and virus cause chewing parts at its tip chew deep into diseases. You have probably heard of yellow starthistle. whirling disease detected in fish when they Yellow starthistle bud weevil Bangasternus swim in a circular fashion. Whirling disease orientalis and hairy weevil Eustenopus villosus in fish is caused by a virus pathogen that were introduced from northern Greece. affects the nervous system. Puccinia jaceae is Yellow starthistle reproduces by seeds. The a yellow starthistle rust fungus that scientists bud weevil and hairy weevil are most are studying to see if it causes damage to effective in the larval stage where they cause yellow starthistle. The rust fungus is found in damage to yellow starthistle seed heads. Both southern Eurasia and the Mediterranean weevils are established in California, Idaho, basin while its original source is Turkey. Oregon,

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