Gordon E. Moore

Mortality factors caused by pathogenic bacteria and fungi of the southern pine beetle in North Carolina

Abstract Phytologic agents were isolated from 22.3% of the broods of southern pine beetles, Dendroctonus frontalis , collected in 1966–1968 from five geographic blocks in North Carolina. Bacteria isolated from dead beetles included Serratia marcescens, Pseudomonas aeruginosa, Bacillus thuringiensis var. thuringiensis, Flavobacterium spp., and several other pathogenic species. Fungi isolated included Fusarium solani, Beauveria bassiana, Aspergillus flavus , and four other pathogenic species. The associated fungal organisms were isolated from both the exterior and interior of the beetles.

Microflora from the alimentary tract of healthy southern pine beetles, Dendroctonus frontalis (scolytidae), and their possible relationship to pathogenicity

Abstract The microflora of healthy larvae and adults of the southern pine beetle, Dendroctonus frontalis , were determined by aseptically excising portions of the fore-, mid-, and hindguts and culturing them on agar. Aerobacter aerogenes, Alcaligenes faecalis , and Serratia marcescens were the principal species of bacteria recovered, and Aspergillus spp. and Penicillium spp. were the principal genera of fungi. Seven of the species recovered were identical with facultative or conditioned pathogens recovered from diseased beetles in other studies.

Moisture requirements of the DD-136 strain of Neoaplectana carpocapsae (Nematoda; Rhabditida) as related to host infection.

Abstract The DD-136 strain of Neoaplectana carpocapsae is capable of continued movement over dry surfaces at 35 and 5 C if relative humidity (RH) ranges above 90%. It can also live in the field on foliage for several hours at night and up to 24 days in bark beetle tunnels in pine bolts. Further nematode research should be directed toward a few insect species where precipitation and RH are suitable for the dispersion of the dauerlarvae. Such areas in the US are located in the Southeast, Northeast, and on the Northwest Coast.

Pathogenicity of ten strains of bacteria to larvae of the southern pine beetle

Abstract The pathogenicity of 10 strains of bacteria to larvae of the southern pine beetle, Dendroctonus frontalis, was determined by orally inoculating healthy larvae. Except for 3 Bacillus spp., these strains had been isolated from healthy or diseased beetles. The Bacillus spp. (B. cereus, B. thuringiensis var. thuringiensis, and B. thuringiensis var. kenyae) as well as Pseudomonas aeruginosa, P. fluorescens, and Serratia marcescens, all from diseased beetles, were pathogenic. Alcaligenes faecalis and Aerobacter aerogenes, both from diseased beetles, and A. faecalis (IK) and S. marcescens (HY), both from healthy beetles, were not pathogenic.

Infectivity of nematodes, Neoaplectana species, for the larvae of the weevil Hylobius pales, after rearing in species isolation☆

Abstract Three nematode strains ( Neoaplectana glaseri , DD-136 Neoaplectana carpocapsae , and Czech Neoaplectana carpocapsae ) that are natural parasites of insects but that have been laboratory-reared many generations in species isolation (i.e., axenically) were tested for infectivity. The trial hosts were larval weevils ( Hylobius pales ) raised from eggs in species isolation (i.e., without symbiotes); 34% became infected with nematodes. Specifically, 35% of weevils exposed to N. glaseri , 31% of weevils exposed to DD-136 N. carpocapsae , and 69% of weevils exposed to Czech N. carpocapsae were parasitized. Since all larval worm stages and reproducing adults were found in some weevils, the “clean” insects were judged to be suitable and sufficient hosts for these nematodes. A pathogenic potential of clean nematode infections was suggested but not proved because of the generally short survival of weevils in species isolation cultures.