North Carolina State Library 

 Raleigh 



N. C. 



Doc. 



University of North Carolina 

 Sea Grant Program 



NEWSLETTER 



APRIL, 1975 



12 35 Burlington Laboratories 

 NCSU, Raleigh, N. C. 27607 Tel: (919) 737-2U5U 



Diking: 



Less dredging 



but more mosquitoes 



Maybe it was just their imaginations. But then, 

 maybe it wasn't. 



Residents of Southport, Wilmington and other 

 coastal communities are almost sure that last year's 

 mosquitoes were about the worst they ever re- 

 membered. 



Some allowed that all the rain last August 

 brought them out. Others speculated that the 

 pesky insects came from nearby dredge spoil 

 islands. 



The islands — built of sand and mud pumped 

 out of channel bottoms by huge dredging machines 

 — aren't new. But a law, put into effect over a year 

 ago, has created new conditions on the islands that 

 some believe are responsible for adding to present 

 mosquito problems. 



The new law requires that spoil dredged from 

 navigation channels be dumped behind walls or 

 dikes built around the islands. Diking is designed 

 to slow the spoil's return to the channels, there- 

 fore reducing dredging's high costs and environ- 

 mental wear and tear. 



But while diking may offer a solution to one 

 problem, it may be the source of another. Accord- 

 ing to Dr. R. C. Axtell, North Carolina State Uni- 

 versity entomologist, observations indicate that 

 diked islands are a large source of mosquito pro- 

 duction. 



Axtell, whose UNC Sea Grant and N. C. Agri- 

 cultural Experiment Station-supported research 

 focuses on coastal insect management, is exploring 

 the relationship between diking and increased 

 numbers of mosquitoes. Axtell's years of coastal in- 

 sect research have made him a world authority in 

 his field. His research in this area, just getting 

 underway, will also examine and evaluate ways to 

 control insect outbreaks on dredge islands. 



(Continued on page 3) 



Dr. R. C. Axtell examines cracks in dried dredge 

 spoil. Cracked spoil creates ideal conditions for mos- 

 quito production. 



mm 



