Some Notes on the Biology of the Apple Sawfly,<i>Hoplocampa Testudinea</i>(Klug)

Dicker, G. H. L.

doi:10.1080/00221589.1953.11513789

Cited by 12 publications

(19 citation statements)

References 2 publications

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“…Consequently, the model predicted a steady increase in the relative abundance of eggs and a similarly regular decrease of adults. Under the given weather conditions the model suggested an average period of 16 days for egg development (50% eggs to 50% larvae) and hence lies in the range of observations made by Miles (1932), Velbinger (1939), Kuenen & van de Vrie (1951), Böhm (1952), Dicker (1953), and Chaboussou (1961). Fifty % of adult mortality was reached after 11 days.…”

Section: Validation Of the Phenology Model For Apple Sawflysupporting

confidence: 62%

The apple sawfly, Hoplocampa testudinea: egg development and forecasting of egg hatch

Graf¹,

Höpli²,

Höhn³

2002

Entomologia Exp Applicata

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The effect of temperature on egg development of the apple sawfly Hoplocampa testudinea Klug was studied under controlled conditions. Based on a linear model describing the relationship between temperature and developmental rates a thermal threshold of 6.9 • C and a thermal constant of 85 day-degrees were established. The experimental results were used to expand and parameterise an existing phenology model to include egg development and hatching of first instar larvae. The model thus became a valuable forecasting tool not only for adult emergence and the optimal monitoring period but also for egg hatch and the best timing of control measures against first instar larvae. The model was validated by comparing predictions with independent observations on egg-laying and subsequent hatching of first instar larvae under semi-field conditions.

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Section: Validation Of the Phenology Model For Apple Sawflysupporting

confidence: 62%

The apple sawfly, Hoplocampa testudinea: egg development and forecasting of egg hatch

Graf¹,

Höpli²,

Höhn³

2002

Entomologia Exp Applicata

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“…The flight period coincides largely with the flowering of apple. The egg‐laying capacity of females is about 32 (D icker , 1954). During oviposition, the female inserts the saw–like ovipositor just below one of the sepals of the flower.…”

Section: Introductionmentioning

confidence: 99%

Impact of the parasitoidLathrolestes ensator(Hym., Ichneumonidae, Ctenopelmatinae) as antagonist of apple sawflyHoplocampa testudinea(Hym., Tenthredinidae)

Zijp

Blommers²

2002

J Applied Entomology

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Lathrolestes ensator (Brauns) was the only parasitoid species reared from larvae of apple sawfly Hoplocampa testudinea (Klug) collected in Dutch orchards. The life history parameters of apple sawfly and its parasitoid L. ensator were investigated in field and semi‐field experiments. Usually, the adult parasitoids emerge in synchrony with the preferred host stage, the second instar sawfly larvae. Parasitoid females carried 120–175 eggs, but never laid more than half this number. The mortality of sawfly eggs and larvae varied from 75 and 99%. The eggs and mining larvae are most vulnerable, as the older larvae survive for 90% on average. Three factors at least determine how many of the descending larvae become adult sawfly or parasitoid next spring. The failure of descending larvae to construct a cocoon varied from 7 to 31% and was highest in clay soil. Probably a similar mechanical hindrance prohibited more emerging adults, of both sawfly and L. ensator, from attaining the surface in heavier soils next spring. Relatively more sawfly prepupae than parasitoids died in the cocoon stage, from fungus disease or other causes, but more parasitoids than hosts stayed in prolonged diapause. Mainly due to this last factor, the overall result was a decrease of the parasitoid : host ratio during the first season underground. A life table based on survival rates during various life stages yields a net reproductive rate of up to 2.4 daughters per female sawfly. It indicates that 60% of the sawfly larvae need to be parasitized to stop population growth, or correspondingly less when more than 75% of the host eggs and young larvae are killed by predators or other causes.

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“…The flight of apple sawfly was monitored in every orchard with visual traps of type Rebell ® (W ildbolz and S taub , 1986) attached on trees at eye level. Two major types of sawfly damage to fruitlets were distinguished: the primary mines, or scars, made by first and second instar larvae (L 1 , L 2 ), and the secondary deep entries of older larvae (L 3 –L 5 ), as defined by D icker and B riggs (1953).…”

Section: Introductionmentioning

confidence: 99%

Apple sawfly Hoplocampa testudinea (Hym., Tenthredinidae) and its parasitoid Lathrolestes ensator in Dutch apple orchards (Hym., Ichneumonidae, Ctenopelmatinae)

Zijp

Blommers²

2002

J Applied Entomology

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Changes in population densities of the apple sawfly Hoplocampa testudinea (Klug) and its parasitoid Lathrolestes ensator (Brauns) were monitored in 15 apple orchards for a period of up to 4 years. The parasitoid species was found in all orchards except one, and was more numerous in plantings on sandier soils. Post‐bloom insecticide applications against other pests, and carbaryl for fruit thinning, often decimated both host and parasitoid in integrated pest management orchards. In organic orchards, where synthetic pesticides are banned, and Quassia is the only remedy against sawfly, the pest is more problematic. The low levels of parasitism in all organic orchards, except one, were possibly due to the application of wettable sulphur during the parasitoid flight period. The sawfly usually recovers more quickly than its parasitoid when chemical control is discontinued, because propagation of L. ensator is limited in various ways. The parasitoid is time limited, because suitable second instar host larvae are rarely available for more than a week on a single apple variety. Moreover, parasitism levels stay moderate because the parasitoid females do not avoid superparasitism. Finally, relatively more sawflies than parasitoids emerge after 10 months underground, because the incidence of prolonged diapause is more elevated in L. ensator than in the sawfly. It is suggested that both the high incidence of prolonged diapause and the inability to avoid superparasitism are useful in reducing the risk of local extinction. Elevated sawfly attack in a single early apple variety would reduce exploitation of suitable host larvae in other nearby varieties, in as far as the parasitoid is not able to distinguish fruitlets with accessible second instar host larvae from those with inaccessible older larvae. Although the former are available for a limited time, the latter may keep the parasitoids from moving to the less abundant second instar larvae in late(r) varieties. Reduction of elevated host density in such an early variety by a properly timed application of a short‐lived pesticide, such as Quassia, increases parasitism levels proportionally, and is expected to promote parasitoid movement to host larvae in other varieties nearby.

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Some Notes on the Biology of the Apple Sawfly,Hoplocampa Testudinea(Klug)

Cited by 12 publications

References 2 publications

The apple sawfly, Hoplocampa testudinea: egg development and forecasting of egg hatch

The apple sawfly, Hoplocampa testudinea: egg development and forecasting of egg hatch

Impact of the parasitoidLathrolestes ensator(Hym., Ichneumonidae, Ctenopelmatinae) as antagonist of apple sawflyHoplocampa testudinea(Hym., Tenthredinidae)

Apple sawfly Hoplocampa testudinea (Hym., Tenthredinidae) and its parasitoid Lathrolestes ensator in Dutch apple orchards (Hym., Ichneumonidae, Ctenopelmatinae)

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