Claim · model-written summary
Aphelinus mali overwinters as full-grown larvae inside its hardened host at Tsingtao.
- Taxon
- Aphelinus mali
Aphelinus malie0 - Outcome
- overwinters in the full-grown larval stagee0
- Setting
- Tsingtao, Shantung Provincee0
Not reportedDirection
Verbatim
e0“Aphelinus mali overwinters in the full-grown larval stage within hardened body of itshost at Tsingtao, Shantung Province.”
Title
Cheng-te Lung; Yun-pei Wang; Peng-gi Tang Acta Entomologica Sinica 1960
Other claims from this paper (19)
- Intervention effect Winter temperatures as low as --12℃ caused little parasite mortality, with adult emergence of 85% at Tsingtao.
- Observation Pupae appeared in late March when ten-day mean temperature reached 6°to7℃.
- Observation The first overwintered adult emerged in mid-April at a ten-day mean temperature of 11℃.
- Observation The lowest emergence temperature was about 10°±1℃, below previously reported temperatures.
- Observation The parasite has about 10--12 generations annually, with a maximum of 13 and minimum of 9.
- Association Temperature during development is the main factor influencing variation in parasite life-cycle duration.
- Observation The overwintering generation lasts 184 days, whereas the shortest generation lasts about 7 days in mid-August.
- Observation Optimal development temperatures are 22°to 27℃ and favorable humidity is 80 to90 per cent, both higher than aphid outbreak conditions.
- Observation In Tsingtao fields Aphelinus mali mainly parasitizes woolly apple aphis and only a few parasitize woolly aphis on Populus canadensis.
- Observation Females seem to prefer oviposition in wax-covered, sluggish aphids rather than merely black aphids.
- Intervention effect Adults survived longest in the laboratory with molasses, up to 41 days.
- Observation Sex ratio varied but females always outnumbered males, and unfertilized females produced only males.
- Association In 1954 egg production per female was 10, 17, 32.4, 58.5 and 21 at temperatures of 16.3℃, 19℃, 23.3℃, 24.2℃ and 26℃ respectively.
- Association In 1955 egg production was 22.7, 29, 44.5, 51 and 28 eggs at 19℃, 21℃, 24.3℃, 26.2℃ and 28.4℃ respectively.
- Association Humidity seemed less important than temperature, but combined high temperature and humidity caused faster adult death and fewer eggs.
- Association Larger females lay more eggs than smaller females.
- Observation A female deposits a maximum of 108 eggs under laboratory conditions at Tsingtao.
- Observation The parasite has difficulty fully controlling the pest throughout the season in Tsingtao.
- Mechanism Limited control is attributed to low reproductive capacity, cold restriction of oviposition and development, early emergence before aphid abundance, and mortality from host shortage.