Host-finding behavior and insecticidal activity of steinernematid entomopathogenic nematodes against the ambrosia beetle, Platypus quercivorus (Coleoptera : Platypodidae).

AbstractDeciduous oak dieback in Japan has been known since the 1930s, but in the last ten years epidemics have intensified and spread to the island’s western coastal areas. The symbiotic ambrosia fungus Raffaelea sp. is the causal agent of oak dieback, and is vectored by Platypus quercivorus (Murayama). This is the first example of an ambrosia beetle fungus that kills vigorous trees. Mortality of Quercus crispula was approximately 40% but much lower for associated species of Fagaceae, even though each species had a similar number of beetle attacks. It is likely that other oaks resistant to the fungus evolved under a stable relationship between the tree, fungus and beetle during a long evolutionary process. Quercus crispula was probably not part of this coevolution. This hypothesis was supported by the fact that P. quercivorus showed the least preference for Q. crispulayet exhibited highest reproductive success in this species. Therefore, P. quercivorus could spread more rapidly in stands with a high composition of Q. crispula. The present oak dieback epidemic in Japan probably resulted from the warmer climate that occurred from the late 1980s which made possible the fateful encounter of P. quercivorus with Q. cripsula by allowing the beetle to extend its distribution to more northerly latitudes and higher altitudes. Future global warming will possibly accelerate the overlapping of the distributions of P. quercivorus and Q. crispula with the result that oak dieback in Q. crispula will become more prevalent in Japan.

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Host-Finding Behavior of the Rice Bug, Leptocorisa chinensis DALLAS (Hemiptera : Coreidae), with Special Reference to Diel Patterns of Aggregation and Feeding on Rice Plant

Applied Entomology and Zoology ◽

10.1303/aez.15.225 ◽

1980 ◽

Vol 15 (3) ◽

pp. 225-233 ◽

Cited By ~ 8

Author(s):

Yooichi KAINOH ◽

Kiichi SHIMIZU ◽

Satoshi MARU ◽

Yoshio TAMAKI

Keyword(s):

Special Reference ◽

Rice Plant ◽

Host Finding ◽

Diel Patterns ◽

Rice Bug ◽

Leptocorisa Chinensis ◽

Host Finding Behavior

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A New Cytosporone Derivative from the Endophytic Fungus Cytospora sp

Natural Product Communications ◽

10.1177/1934578x1400900723 ◽

2014 ◽

Vol 9 (7) ◽

pp. 1934578X1400900 ◽

Cited By ~ 1

Author(s):

Tomoya Takano ◽

Takuya Koseki ◽

Hiromasa Koyama ◽

Yoshihito Shiono

Keyword(s):

Antimicrobial Activity ◽

Endophytic Fungus ◽

2D Nmr ◽

Ambrosia Beetle ◽

Oak Wilt ◽

Tree Disease ◽

Platypus Quercivorus ◽

Mass Spectral ◽

Screening Study ◽

Raffaelea Quercivora

Japanese oak wilt (JOW) is a tree disease caused by the fungus Raffaelea quercivora, which is vectored by the ambrosia beetle, Platypus quercivorus. In a screening study of the inhibitory active compounds from fungi, a new cytosporone analogue, compound 1, was isolated from the endophytic fungus Cytospora sp. TT-10 isolated from Japanese oak, together with the known compounds, integracin A (2), cytosporones N (3) and A (4). Their structures were determined by extensive 1D– and 2D–NMR spectroscopic and mass spectral analyses. Compound 1 was identified as 4,5-dihydroxy-3-heptylphthalide and named cytosporone E. Compounds 2 and 3 showed antimicrobial activity against Raffaelea quercivora.

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