/. Pests and Human Disturbance. Insect damage has occurred in limited areas from 

 several different organisms (Table 51). One is a larval borer which occurs within sea oats 

 stems near ground level; the plant typically turns brown and rots at or below the ground 

 surface. Another, also a larval borer, smoothly cuts the stems of sea oats at an angle around 

 the base of the plant up to 6 inches below the surface. Local infestations on the 1,200-foot 

 sea oats dune have resulted in kills in areas of 5 feet in diameter; however, insect destruction 

 has not been a problem in maintaining any of the dunes. Beetle damage to seed heads of sea 

 oats is prevalent, but is not considered a problem unless seed production is desired. 



Table 51. Collected insects winch attack vegetation or reproductive material of sea oats. 1 



Order 



Family 



Species 



Coleoptera 



Melyridae 



Collops sp. (adult) 





Mordellidae 



Mordellistena sp. (larvae) 





Elateridae 



Glyphonyx sp. 





Tenebrionidae 



Pechalius pilosus (Champion) 



Hemiptera— Homoptera 



Pseudococcidae 



Distichlicoccus salinus (Cockerell) 



Hymenoptera 



Encyrtidae 



Anagyrus sp. 



Lepidoptera 



Pyralidae 



Rupela sp. 



1. Identified by Agricultural Research Service, USDA, Beltsville, Maryland. 



Jackrabbits (Lepus calif ornicus) regularly grazed exposed leaves of bitter panicum on 

 established plantings, but were confined to small areas and had little effect on dune growth. 

 However, on fresh plantings, especially of sea oats and recently (1973-74) bitter panicum, 

 jackrabbits have caused severe, although sporadic, damage. The sea oats transplant was 

 usually pulled from the ground, and chewed through at its base. Entire plantings have been 

 decimated; e.g., the 1970 Pan Am sea oats planting, and the south half of the 1,200-foot 

 dune-width planting, consisting of 10,000 transplants each, were totally destroyed. Most 

 plantings remained untouched, wliile others suffered only light damage. Damage was 

 unpredictable in extent and time of occurrence, and on one or several nights, from 

 immediately to a month or more after planting. Before 1973, no damage to bitter panicum 

 was observed. Jackrabbits would often destroy a row of sea oats while leaving an adjacent 

 row of panicum untouched. In 1973-74, rabbits damaged bitter panicum culms more 

 regularly than sea oats, and showed a preference for them. Damage to panicum was not 

 detrimental to survival of the culm, since the exposed culm was chewed off at or near the 

 base rather than pulled from the ground. Only in areas of drifting sand would ground-level 

 pruning of panicum be harmful, since an undamaged plant may not be entirely buried or 

 smothered, while a damaged plant may be covered with too much sand to penetrate. 



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