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FreshPlaza

Publication date: 3/23/2015

eight_col_064_IS09AL1QZFarmer with basket of organic potatoes.

New research shows a plastic mesh cover laid over potato crops could be the answer to fighting potato pests without using chemical sprays.

Scientists at the Future Farming Centre and Lincoln University say field trials of the mesh cover is showing exciting results in controlling the tomato potato psyllid as well as reducing potato blight.

The psyllid arrived in New Zealand in 2006 and can cause severe crop loss through its bacterium.

Researchers Dr Charles Merfield said the trials over two growing seasons in Canterbury showed potatoes under the mesh covers had reduced numbers of psyllids, increased tuber size and an increase in overall yield.

He says the covers were widely used in other countries and he expected them to become popular in New Zealand.

“These mesh crop covers have been in use in Europe for probably nearly two decades now, so they’re very widely used over there for pest control, particularly amongst organic growers, so these strike me as being an ideal way of controlling psyllids on potatoes on field crops.

“We did some initial trials at the Future Farming Centre and we’ve got some very good results in terms of controlling psyllid – and we also got the surprise effect of a dramatic reduction in potato blight as well.”

Dr Merfield said the mesh could also control a wide range of pests on many different field crops and was being used by organic growers in Hawke’s Bay to control root fly on carrots.

Source: radionz.co.nz

http://www.freshplaza.com/article/137097/NZ-Mesh-cover-to-fight-potato-pests?utm_campaign=newsletter&utm_medium=ed5&utm_source=s1

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January 20, 2015 by Entomology Today

From  pestnet@yahoogroups.com

Are Asian Citrus Psyllids Afraid of Heights? Elevation Study May Provide Clues for Stopping Them

Asian psyllid

The Asian citrus psyllid, Diaphorina citri, was first discovered in Florida in 2005 and in Puerto Rico in 2007. Since then it has caused billions of dollars’ worth of damage by spreading a bacterium which is responsible for citrus greening disease (Huanglongbing), the most serious disease of citrus in the world. However, scientists from the U.S. Department of Agriculture’s Agricultural Research Service (USDA-ARS) in Puerto Rico and Florida have discovered that the ACP doesn’t do well at high elevations for reasons that are not yet known. Their research, which may one day lead to clues about the insect’s vulnerabilities, is published in the Journal of Economic Entomology.
After hearing anecdotal evidence that the ACP is less abundant at high elevations, Drs. Dave Hall, David Jenkins, and Ricardo Goenaga set up a two-year experiment to find out for themselves. They chose 17 different sites, ranging from 10 to 880 meters above sea level, which were monitored with yellow sticky traps on citrus trees or other plants that are preferred by the ACP.
As elevations increased, ACP populations decreased, dropping to zero when they reached 600 meters or more above sea level.
Asian psyllid nymphAn Asian citrus psyllid nymph.
“There was a strong trend in both years for decreasing psyllid abundance with increased elevation based on the number of psyllids captured on traps and the proportion of trees shown to be infested,” they wrote. “No psyllids were collected at an elevation of >600 m.”
In addition, none of the trees surveyed for citrus greening disease at high elevation sites tested positive.
What does this mean for citrus growers?
Changes in elevation result in changes in temperature, short-wave radiation, partial pressure of respiratory gasses, precipitation, oxygen content, and air pressure. If any of these can be shown to affect the development of the ACP or of citrus greening disease, then it may be possible to induce these conditions in citrus trees at lower elevations.
“Another practical implication for this study would be to put citrus nurseries >600m, where numbers of D. citri are minimal to non-existent,” according to the authors.

Open Access paper at:
– Diaphorina citri (Hemiptera: Liviidae) Abundance in Puerto Rico Declines with Elevation

J. Econ. Entomol. 1–7 (2015); DOI: 10.1093/jee/tou050
ABSTRACT Diaphorina citri Kuwayama is the primary vector of Huanglongbing, the most devastating disease of citrus. D. citri populations in Puerto Rico were monitored with yellow sticky traps on citrus trees or other psyllid host plants at different elevations, ranging from 10 to 880m above sea level. Trapping was conducted in March through May of 2013 and 2014 when psyllid populations usually are highest. Population levels of D. citri, based on the trapping data, varied among the sites, and there was a strong trend in both years for decreasing psyllid abundance with increased elevation based on the number of psyllids captured on traps and the proportion of trees shown to be infested. No psyllids were collected at an elevation of >600 m. Reduced populations at higher elevations could be a consequence of differences in temperature, air pressure, oxygen levels, ultraviolet light, or other factors alone or in combination. We discuss our results as they pertain to management of D. citri and Huanglongbing.


Dr. Ulrike Krauss
Invasive Species Consultant
P O Box GM1109
Saint Lucia
Tel. (+1 758) 713 4308
Skype: ulrike_krauss
E-Mail: saintlucia.ias@gmail.com
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