Alien insects danger to state trees, crops

Published 12:00 pm Friday, September 27, 2013

There are five insects that have been identified as pests in Mississippi and are affecting commercial growers and native plant life. All five insects are not native to the United States and are becoming a problem for many people in the state.

Blake Layton, an entomologist with the Mississippi State University Extension Service, said the spotted wing drosphilia, bermudagrass stem maggot, kudzu bug and redbay ambrosia beetle are originally from different parts of Asia. Joe MacGown, a research technician with the Mississippi Entomological Museum, said the tawny crazy ant is thought to originate from Argentina or Brazil.

The population of introduced insects to Mississippi has grown over the last 10-15 years, MacGown said. Currently, 30 species of introduced insects have been identified in Mississippi, when 10 years ago that number was about one third the current count.

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In an interview with “LandMarks,” Layton said, “all three pests (spotted wing drosphilia, bermudagrass stem maggot, kudzu bug) came from Asia and are here to stay. They are expected to cause significant economic losses in the crops they affect.”

Layton said the spotted wing drosphilia, bermudagrass stem maggot and kudzu bug have started to affect the commercial growers in the state. He said the spotted wing drosphilia is related to the fruit fly and attacks fruit that is beginning to ripen.

The spotted wing drosphilia lay their eggs in the fruit and the eggs hatch small, white, maggots before the fruit has even been picked.

Layton said the drosphilia was first identified along the Mississippi coast in 2010, but started affecting commercial harvests this year, including blueberry harvests.

He said some commercial growers have found insecticide sprays to protect their harvest, but it was something that was not needed before. Since the spotted wing drosphilia has been introduced to the United States, it has cost the commercial fruit industry over $1 billion in lost revenue.

The bermudagrass stem maggot is not a danger to Pearl River County residential lawns, but it is becoming a problem for those who sell hay commercially, Layton said.

Layton said the maggots get into the stems of the grass and effect the growth. He said the reason it is not a danger to lawns is because of the frequency homeowners mow their lawns. Consistent lawn maintenance keeps the maggot from becoming a problem for homeowners.

Layton said he is working on research to see how serious of a problem the maggot poses and to look into options to control the bermudagrass stem maggot population.

The kudzu bug feeds on kudzu, a vine brought to the United States at the beginning of the 20th century to help with erosion control, but the bug has now become a significant threat to soybean crops, Layton said.

He said the kudzu bug builds up huge numbers in the fall and the adults accumulate on the sides of buildings.

Kudzu bugs have a very foul odor and are nuisances to homeowners who find the bugs on their houses or buildings. Layton said the kudzu bugs are attracted to lighter colored buildings, especially white buildings.

“As this thing colonizes (in) Mississippi, we’re going to see more and more problems with the kudzu bug,” Layton said.

The kudzu bug has been found in about a quarter of the state’s counties and Layton expects that number to grow as fall approaches.

The redbay ambrosia beetle is becoming a problem for the redbay tree and could harm the future of Cajun cuisine. Redbay leaves are traditional ingredients used in Cajun recipes.

According to a Mississippi State University Office of Agriculture publication, “The beetle is the redbay ambrosia beetle, a dark brown insect about half the size of an uncooked grain of rice. It spreads the pathogen that causes Laurel wilt disease in many tree species, including Mississippi’s redbay and sassafras trees.”

Layton said the beetle has eradicated the redbay tree population in other states with the problem and that there is currently no preventative treatment. Once the beetle inoculates the tree with the fungus, the tree will die.

Layton said while it does attack sassafras trees, it’s less deadly to their type of tree.

A new ant found along the Mississippi Gulf Coast is becoming a problem for home and business owners. Layton said the tawny crazy ant was first identified in Bay St. Louis in 2009.

MacGown said the tawny crazy ant has now been identified in Hancock County, Harrison County and Jackson County, but in isolated spots of the counties.

The ant doesn’t sting like traditional ants, but that “the numbers are so great” that it causes problems, Layton said.

“This one, when it’s present, it’s more numerous than any other insects I’ve ever seen,” Layton said.

MacGown said the ants have even caused problems in their native locations of Argentina and Brazil, which he said is unusual with native species.

Layton said when he visits properties that have been infested, the buildings usually have electrical problems because the ants will get inside and the large amount of ants causes electrical problems.

MacGown said they’re attracted to electricity and will find their way into electrical outlets, electrical boxes and even computers. Once they have found a location, the ant will release a pheromone that will recruit additional ants.

Both MacGown and Layton said that on infested properties, you can’t even walk without the ants covering your feet.

MacGown said the tawny crazy ant is not one you can eradicate without professional help. If a homeowner notices a problem, a professional should be called in and it will take time and many steps to eradicate the ants from your property. He said if you can, try to work with your neighbors to develop a plan to keep the ants from moving to another property and then returning to your property.

“We are finding them in more and more locations. It could be an indication that things could get worse,” MacGown said.