外国産マツ属の虫害に関する研究 : 第1報 マツノシンマダラメイガについて

Abstract

京都大学上賀茂育種試験地に植栽されている外国産マツ属のうち30種とアカマツ, クロマツの, 32種を対象にその生育状況およびマツノシンマダラメイガによる被害状況を1960 ~ 1962年にわたって調査し, つぎのことが判明した｡ 1. 虫害をうけないで健全に生育すれば P. elliottii, P. massoniana, P. pinaster, P. radiata, P.taeda の生育は良い｡ 2. 上賀茂育種試験地でマツノシンマダラメイガの被害をうけている種はつぎの19種である｡ すなわち, 激害をうけている種 P. radiata, P. pinaster, P. sylvestris, P. sylvestris v. rigensis, P. muricata 中害をうけている種 P. massoniana, P. banksiana, P. ayacahuite, P. ayacahuite v. brachyptera 微害をうけている種 P. densiflora, P. ponderosa, P. elliottii, P. excelsa, P. laricio v. carsicana, P. laricio v. calabrica, P. patula, P. peuce, P. taeda, P. torreyana 3. 本調査でマツノシンマダラメイガの被害がみられなかったのはつぎの13種である｡ しかしこのうちで◦印をつけた4種はその被害が報告されている｡ すなわち, P. armandi, ◦P. australis, ◦P. echinata, P. jeffreyi, P. laricio v. pallasiana, P. nigra, P. nigra v. austiriaca, P. pinea, P. pungens, P. rigida, ◦P. strobus, ◦P. thunbergii, P. virginiana 4. マツノシンマダラメイガの被害は樹幹, 新梢, 毬果のいずれにもみられたが, 毬果の被害は今のところ P. sylvestris だけである｡ 5. 被害種のうち, 樹幹のみに被害がみられるのは P. patula で, 新梢のみに被害がみられるのは P. ayacahuite, P. larcio v. corsicana, P. laricio v. calabrica, P. peuce, P. torreyana でその他の種は樹幹, 新梢ともに加害されている｡ しかし, P. pinaser は樹幹の被害が激しく, P. ayacahuite v. brachyptera, P. banksiana, P. ponderosa, P. excelsa, P. massoniana, P. muricata は新梢の被害が目立っている｡ 6. 新梢は側枝の新梢よりも主軸の新梢の被害が激しく, このために被害木は樹形が悪くなり, 樹幹を激しく加害されたものでは被害部より折れる危険がある｡ 事実, P. pinaster では第2室戸台風で被害部より折損したものがかなり多数あった｡

In this report, the authors deal with some observations on the attacks of shoot moth (Dioryctria splendidella H. - S.) upon thirty imported pine-species and two native pine-species (Pinus densiflora, P. thunbergii) from 1960 to 1962, which were planted in the Kamigamo Breeding Experimental Forest Station of Kyoto University. The results obtained from these observation are as follows: -- 1. Under the natural conditions of this plantation, the growth of P. pinaster, P. radiata, and P. taeda was better than the other imported pines. 2. In Kamigamo, nineteen pine-species were infested with the larvae of this shoot moth, that is; the damages were severe in the following species: P. radiata, P. pinaster, P. sylvestris, P. sylvestris v. rigensis, P. muricata. the damages were moderate in: P. massoniana, P. banksiana, P. ayacahuite, P. ayacahuite v. brachyptera the damage was slight in: P. densiflora, P. ponderosa, P. elliottii, P. excelsa, P. laricio v. corsicana, P. laricio v. calabrica, P. patula, P. peuce, P. taeda, P. torreyana 3. In Kamigamo, the following thirteen pine-species were not damaged, but four species marked "*" were host to this shoot moth, (as had been reported by some persons already.) P. armandi, *P. australis, *P. echinata, P. jeffreyi, P. laricio v. pallasiana, P. nigra, P. nigra v. austriaca, P. pinea, P. pungens, P. rigida, *P. strobus, *P. thunbergii, P. virginiana 4. This shoot moth caused an injury to the stem, shoot and cone, but the damage to the cone was found upon P. sylvestlis only. 5. Among the damaged trees, the damage in P. patula was found only in the stem, in P. ayacahuite, P. laricio v. corsicana, P. laricio v. calabrica, P. peuce, P. torreyana, the damage was found only in the shoot. In the other damaged trees, the larvae of this shoot moth were found both in the stem and in the shoot, and the stem-damage of P. pinaster was the severest, in the case of P. ayacahuite v. brachyptera, P. banksiana, P. ponderosa, P. excelsa, P. massoniana and P. muricata, the shoot-damage was conspicuous. 6. As compared with the top-shoot-damage and the side-shoot-damage, the top-shoot-damage was sreatest. Therefore the stem of the damaged tree was not straight. When the stem-damage is the severest, the damaged tree can be snaped at the infested portion. Actually, we can find an illustration of P. pinaster damaged by the typhoon second Muroto.