Sunday, May 1, 2016

New mite found in Lancaster, Pa.

A new pest that destroys leeks, onions, garlic, chives, shallots and green onions has spotted in Lancaster, Pa., says the state department of agriculture.

A tiny allium leafminer fly was discovered for the first time on a farm in Lancaster County in December and has since been identified in four other counties, including Chester, Dauphin, Delaware and Lehigh, reports Olena Goncharova of the Pittsburgh Post-Gazette.

It’s the first time in has been identified in the Western hemisphere.

“For our farmers an infection of this pest could mean a loss in production of allium crops. And for our consumers, this could result in a lack of availability of these crops for consumption,” Agriculture Secretary Russell Redding said.

The allium leafminer, or Phytomyza gymnostoma, was first detected in 1850 and in 2003 was spotted in the United Kingdom. 

It has affected farms in Poland and Germany, and has been reported in Asia, Turkey, parts of Russia and Turkmenistan. 

Adult leafminers are about three millimeters long and look like gray or black flies with a distinctive yellow or orange patch on the top and front. 

They show up at the end of winter and lay eggs at he base of plant stems from March to May. 

The eggs are white, about 0.5 millimeters in length and slightly curved. Infected plants usually have wavy, curled and distorted leaves with a row of white dots.

Leafminers are most likely transported with commercial cargo or in passenger baggage. They frequently escape detection at ports of entry.

There is a lot of Mennonite traffic between farms in Lancaster County and Ontario.

Scientists are still working to understand the nature of this species. Shelby Fleischer, a Penn State professor of entomology, says it’s too early to predict the damage it may cause and how fast this pest might spread across the country, but it could be a “significant problem.” 

More studies need to be done, Mr. Fleischer said.

Previous research show that the pest can be more damaging in organic, non-commercial farms or homeowner gardens. Then are no threat to human health.

A delay in planting, which normally begins in March for fall for allium crops such as leeks, can be used to minimize crop exposure. 

Covering onion, chive and garlic plants before the emergence of adults, and keeping plants covered could keep leafminers out. European growers also used pesticides.

Farmers and gardeners can submit photos of damaged crops to to help with identification and obtain advice.