Scouting Notes - May 2008

Biologicals provide thrips control. For biological controls to be effective on western flower thrips,  prophylactic introductions should start on young plants or in propagation areas, University of Connecticut greenhouse IPM specialist Leanne Pundt said.

Neoseilus cucumeris is a small, predatory mite that feeds on young first instar thrips larvae. Hypoaspis miles or H. aculifer is a soil-dwelling predatory mite that feeds on pupal stages of thrips in the soil as well as fungus gnat larvae. Predatory rove beetles, Atheta coriaria, feed upon thrips as well as shore flies and fungus gnats. The predatory mite, Amblyseius swirskii, feeds upon both thrips and whiteflies. Apply Beauveria bassiana (fungal spores) early in the cropping cycle to ensure thorough coverage and before plants flower and produce pollen, which increases thrips egg laying. Steinernemia feltiae, an entomopathogenic nematode, used primarily against fungus gnat larvae, also attack thrips pupae and prepupae found in the growing medium.

For more: Leanne Pundt, University of Connecticut, (860) 626-6240; leanne.pundt@uconn.edu; www.negreenhouseupdate.info.

California announces LBAM eradication plan. California Department of Food and Agriculture and USDA have completed an action plan outlining 2008 strategies to eradicate the light brown apple moth from the state’s Central Coast and Bay Area communities. It will likely take several years to eradicate LBAM. The primary tool for eradication will be aerial treatment with LBAM moth pheromone. Treatments are expected to begin June 1 in Monterey and Santa Cruz counties.

A USDA study indicates that if California becomes generally infested, the moth would cause between $160 million-$640 million in crop damage annually. It would hinder export opportunities and interstate commerce due to quarantine restrictions.

For more: California Department of Food and Agriculture, (916) 654-0462; www.cdfa.ca.gov/lbam

Avoid overwatering to limit springtail populations. Springtails are very small, wingless arthropods about 1/16-1/8 inch long. University of Massachusetts extension floriculture specialist Tina Smith said springtails occasionally are observed in greenhouse growing media, especially if plants have been overwatered.

Springtails have chewing mouthparts, but rarely damage the roots or leaves of greenhouse ornamental plants. They also do not vector diseases.

A few species feed on living plants and are occasionally regarded as pests. Outdoors, Bourletiella hortensis (garden springtail) may damage seedlings in early spring. As they feed, small holes and surface scarring develops. Some species also feed on roots. Most types of springtails are beneficial by reducing decayed vegetation to soil. To reduce populations avoid overwatering and allow the growing medium to dry between waterings.

For more: Tina Smith, University of Massachusetts-Amherst, (413) 545-5306; tsmith@umext.umass.edu.

Anise essential oils fight fungus, aphids. The fungal plant pathogen Colletotrichum has been able to be controlled in laboratory tests using essential oils of Pimpinella spp. (anise), which have high levels of organic mixtures called phenylpropanoids.

Nurhayat Tabanca and plant pathologist David Wedge at USDA’s Agricultural Research Service’s Natural Products Utilization Research Laboratory in Oxford, Miss., found one phenylpropanoid compound was especially effective against strawberry anthracnose and strawberry soft rot and leaf blight.

Researchers also found P. isaurica essential oils were more effective in controlling aphids than isolated Pimpinella phenylpropanoids. This research could lead to Pimpinella essential oils as a source of agrochemical agents.

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For more: Natural Products Utilization Research Laboratory, (662) 915-1009; www.ars.usda.gov/is/pr/2008/080220.htm.

May 2008