Unaspis Yanonensis Research Articles

A study of the relationship between pesticide treatment and the fauna in citrus groves on Nagashima Island, Kagoshima Prefecture.

This is our third report on the effect of agrochemical treatment to the insect and mite fauna at two native citrus groves of ‘Kuroshima-mikan’. The groves are located in Kasedo and kawatoko on the island of Nagashima, Kagoshima Prefecture. In Kasedo, spraying was practiced in 1974-85 but there was no (or no heavy) spraying from 1986-92. On the other hand in Kawatoko, which was left unsprayed until 1985, only petroleum oil was used once a year (in January) in 1986-87 and in 1990-92. In Kasedo, Panonychus citri (citrus red mite) maintained a high population until 1986, probably because of the poor fauna of its natural enemies due to the spray of insecticides. In Kawatoko, Unaspis yanonensis (arrowhead scale) dropped in numbers from 1986 due to the use of petroleum oil. Kawatoko had a rich fauna of insects, especially the effective predators and parasitoids of insect and mite pests. The use of petroleum oil in winter (once a year) was effective against scales and eventually against mites and whiteflies whose natural enemies were uninhibited by the petroleum oil.

PREDATION OF THE LADYBEETLE CHILOCORUS KUWANAE ON THE SCALE UNASPIS YANONENSIS

Abstract The prey consumption of ovipositing female adults of the ladybeetle Chilocorus kuwanae on the scale Unaspis yanonensis was found to be significantly greater than that of the male adults. At 25°C one female adult ladybeetle, on average, would consume 42. 7 female scale adult per day while one male adult only destroyed 22. 3 female scale adults. However, after a deprivation of the prey for 48 h, this difference was eliminated. A C. kuwanae female adult had to prey on at least 15 U. vanonensis female adults in order to lay eggs. The funcional responses of the beetle adults to densities of different stages of the scale followed Holling's type 1. The functional responses to female scale adults indicated that the maximum prey consumption went up with the increase in temperature from 16°C to 35°C, and dropped sharply at 37°C. However, temperature did not alter the type of the functional response. Rased on the predation of C. kuwanae adults on U. yanonensis female adults, the minimum critical, optimal and maximum critical temperatures for their attack were estimated to be 10. 6°C, 31. 5°C and 38. 2°C respectively. The increase in predation space or in predator density could result in a reduction in the attack rat‐e, but with the increase of predator density, the effect of predation space became much smaller. C. kuwanae adults preferred male pupae to other stages of the scale, and their preference for various stages of the prey was in the order of male pupae, 2nd‐instar male nymphs, 2nd‐instar female nymphs, adult females and kinstar nymphs.

A Simulation model for the arrowhead scale (Hemiptera: Diaspididae) population dynamics on citrus trees in relation to pest‐management programs

1. A mathematical model was constructed describing population dynamics of the arrowhead scale,Unaspis yanonensis Kuwana. The population occurrence patterns simulated by the model from 1971 to 1976 were relatively consistent with the actual findings in the field. 2. The effects of control tactics for this pest were examined on the basis of the model. 3. Effective timing of insecticide (petroleum oil and organophosphorous insecticide) application was indicated to be 40 days after the initial appearance of 1st-instar nymphs in both the 1st and 2nd generations of the host. 4. The number of overwintering adult females in May of the next year (i.e., the starting point of the next year’s population) decreased linearly with the increment in the degree of insecticide coverage. The pest populations were expected to be kept to low densities by petroleum oil sprays alone for the 1st generation when overall, complete coverage was accomplished. 5. Examination of the effects of two introduced parasitoids,Aphytis yanonensis andCoccobius fulvus, showed that they were able to control the scale population by themselves when more than 70% parasitism was achieved. When petroleum oil was applied to overwintering adults (termed winter petroleum oil) at the degree of coverage of 0.8, host populations were reduced by ca. 60% parasitism. When the winter petroleum oil was combined either with additional petroleum oil 40 days after the initial appearance of 1st-instar nymphs of the 1st generation or with an organophosphorous insecticide 40 days after the initial appearance of 1st-instar nymphs of the 2nd generation (degree of coverage=0.8 in each case), 40% parasitism led the reduction of the pest population. 6. The most desirable control program was considered to be one in which winter petroleum oil was used every year and additional petroleum oil or an organophosphorous insecticide was also used in those years when host density was high.

Synergism of acephate on the control of synthetic pyrethroids against the arrowhead scale Unaspis yanonensis, KUWANA

Synergism of acephate on the control of synthetic pyrethroids against the arrowhead scale <i>Unaspis yanonensis</i>, KUWANA

ヤノネカイガラムシ第1世代に対するブプロフェジン剤の防除効果

ヤノネカイガラムシ第1世代に対するブプロフェジン剤の防除効果

Oviposition stimulants in the coccoid cuticular waxes ofAphytis yanonensis De Bach &amp; Rosen

Aphytis yanonensis De Bach & Rosen, a parasitic wasp of the arrowhead scale,Unaspis yanonensis (Kuwana), was introduced to Japan to controlU. yanonensis. A. yanonensis recognizes a host insect by antennal contact and deposits eggs on the insect body underneath the scale. Ovipositional behavior is induced by perceiving the cuticular wax of the host insect,U. yanonensis, and other coccoids. Chemical composition of the cuticular wax was analyzed and oviposition stimulants were isolated following a bioassay usingA. yanonensis.

ヤノネキイロコバチ放飼園におけるヤノネカイガラムシ寄生果率の年変化

Annual changes in adult female density and fruit infestation rate of the arrowhead scale, Unaspis yanonensis, were examined from 1983 to 1988 at a citrus orchard where the parasitoid, Aphytis yvanonensis, was released in 1982. After the release the scale density and the fruit infestation rate decreased. However, the fruit infestation rate exceeded 0.1. A positive relationship between the scale density and the fruit infestation rate was observed. This relationship suggests that we need to suppress the density of U. yanonensis females below 0. 013 per leaf in November so as to maintain the fruit infestation rate under 0. 05. It seems difficult for A. yanonensis to keep the pest population at such a low level. Most of the scales present on fruits were dead and only caused cosmetic damage of the fruits. These results suggested that we should adopt alternative economic thresholds not based on cosmetic damage of fruits in order to use natural enemies to control the pest practically.

Fragrant and biologically active constituents of the citrus cultivar jyabon

1,8-Cineol is probably a key material for the fragrance characteristic of the fruit of jyabon. Further, the peels of this citrus contain psoralen which has pesticidal activity against Unaspis yanonensis (arrowhead scale insect). The flowers contain a large amount of β-myrcene which attracts Oxycetonia jucunda (citrus flower chafer). The composition of essential oil constituents of the leaves is similar to that of Citrus grandis var. anseikan.

導入天敵によるヤノネカイガラムシの生物的防除 ＩＩＩ ヤノネカイガラムシの増殖に及ぼす寄生蜂の影響

導入天敵によるヤノネカイガラムシの生物的防除 ＩＩＩ ヤノネカイガラムシの増殖に及ぼす寄生蜂の影響

導入天敵によるヤノネカイガラムシの生物的防除 Ｉ あま美大島における放飼効果

導入天敵によるヤノネカイガラムシの生物的防除 Ｉ あま美大島における放飼効果

Biological control of arrowhead scale,Unaspis yanonensis, by parasitic wasps introduced from the People's Republic of China

In 1980, the authors went to the People's Republic of China in search of the natural enemies of the arrowhead scale,Unaspis yanonensis Kuwana, and succeeded in collecting 2 species of parasitic wasps of this pest namelyPhyscus fulvus Compere & Annecke andAphytis yanonensis DeBach & Rosen.

ヤノネキイロコバチの予備的放飼試験

In 1980 Aphytis yanonensis DEBACH et ROSEN was introduced from China into Japan to control the arrowhead scale, Unaspis yanonensis (KUWANA). A preliminary release test of the parasitoid was conducted in Fukuoka to determine the effectiveness of the parasitoid. In June 1982, 200 females of the parasitoid were released in a grove containing 25 citrus trees. Percent parasitism gradually increased until it reached 67 in February 1983. Number of generations during this period was estimated to be about 8 based on the effective accumulation temperature. The parasitoid which was found in October 1982 in a citrus grove about 15 m distant from the grove where it had been released could not be detected in February 1983 in a citrus grove about 600 m distant from it.

中国からのヤノネカイガラムシの天敵導入 その経過と期待される成果

The arrowhead scale insect, Unaspis yanonensis (KUWANA), is an exotic and key pest in citrus orchards in Japan. Much efforts have so far been paid to the introduction and establishment of parasites. Based on available information and studies on the parasite of the scale, efficient parasites were considered to be distributed in a few localities in China. In 1980 two Japanese entomologists succeeded to collect two species of parasite, Aphytis sp. and Physcus fulvus COMPERE et ANNECKE, at the suspected places, Chungking and Chengtu in Szechwan Province. It is said that the arrowhead scale in these areas is controlled naturally at economic injury levels. Since ecological conditions of Japanese citrus areas are similar to those of the parasite native home, their establishment and efficiency as natural enemies in Japan will be promised. This success has been achieved under the cooperation of many people in the world, and this record reported here will contribute in future to the planning of the introduction of natural enemies of exotic instct pests from native homes.

南西諸島のヤノネカイガラムシとその捕食性天敵

南西諸島のヤノネカイガラムシとその捕食性天敵

ヤノネカイガラムシに対するAphytis sp. &quot;A&quot; の適応性について

ヤノネカイガラムシに対するAphytis sp. &quot;A&quot; の適応性について