A New Look at Cultivar Preference in Hoplocampa testudinea (Hymenoptera: Tenthredinidae) on Apple in the Annapolis Valley of Nova Scotia, Canada

(1) Background: The European apple sawfly, Hoplocampa testudinea Klug (Hymenoptera: Tenthredinidae), can be an economically important pest in eastern Canada and shows preference for apple cultivars in Nova Scotia, Canada. We hypothesized that this preference could be due to oviposition by female H. testudinea (preference-performance hypothesis) during the bloom period or differential larval survival during development due to fruitlet physicochemical properties. (2) Methods: Fifteen commercial and experimental apple (Malusdomestica Borkh.; Rosaceae) cultivars located at the Kentville Research and Development Centre (Kentville, Nova Scotia) were chosen and examined for H. testudinea oviposition, larval performance during fruitlet development, fruitlet physicochemical properties and damage assessment at harvest from 2016–2019, inclusive. (3) Results: H. testudinea showed significant cultivar preference during oviposition, during development and at harvest, but the ranking of these cultivars was not the same throughout the season. Total impact by H. testudinea was consistent for most cultivars over multiple years of the study. (4) Conclusion: Correlation of oviposition with damage provided weak evidence for the preference-performance hypothesis. We propose that this relationship is weak due to differential survival of larvae during development.

Bioecology, Harm And Efficiency Of Certain Preparations Against The Apple Fruit Sawer (Hoplocampa Testudinea Klug.)

This article provides data on the harmfulness, distribution and lifestyle of the apple sawdust widely noted in recent years in the intensive orchards of the republic. In order to determine the effectiveness of insecticides against olm arrakashi, observations were first carried out based on the sex pheromone. On this basis, in three variants, the drugs Dalate Plus 10% ae, Entovant 15% ae, Protect 5% em.k were tested, a higher efficiency was observed in the variant where the drug Dalate Plus 10% ae was used, - 0,2 l / ha, where the biological efficiency was 86.7% in comparison with the control.

Apple cultivar preferences by Hoplocampa testudinea (Hymenoptera: Tenthredinidae) in the Annapolis Valley of Nova Scotia, Canada

The European apple sawfly, Hoplocampa testudinea (Klug) (Hymenoptera: Tenthredinidae), is an economically important pest in eastern Canada. Growers can experience significant crop losses as management of this species is difficult because it is present during bloom. As a result, management strategies other than pesticides are required for this pest. Eleven commercial and experimental apple (Malus pumila Miller; Rosaceae) cultivars were studied to evaluate host resistance as a potential management strategy. Preferences were determined using field surveys of adult visitation, larval infestation of apples, damage at harvest, behavioural bioassays, and electrophysiological tests. Significant differences in visitation and infestation were observed. H. testudinea preferred “Zestar!”, “s23-06-153”, and “Pinova” over other cultivars examined. Comparison with subsequent larval counts and damage also suggest differential performance of larvae in several cases, irrespective of the adult preference. Y-tube bioassays and electroanntennography results indicate that olfaction plays a role in cultivar discrimination for this species.

Monitoring of Sawfly Populations (Hymenoptera, Symphyta: Hoplocampa Spp.) In Plum And Apple Orchards Using Visual Traps

The investigation of Hoplocampa minuta (Christ, 1791) (black plum sawfly), Hoplocampa flava (Linné, 1760) (yellow plum sawfly) and Hoplocampa testudinea (Klug, 1816) (apple sawfly) populations using white sticky traps Rebell®bianco was carried out in conventionally and organically managed apple and conventionally managed plum orchards of the Institute of Horticulture of Lithuanian Research Centre for Agriculture and Forestry in 2010 and 2011. Temperature sums for predicting sawfly spring emergence were determined: 120 ± 5 degree-days for apple sawfly, 85 ± 26 degree-days for black plum sawfly and 95 ± 28 degree-days for yellow plum sawfly. However, more years of the study are needed to confirm these temperature sums. The average densities of sawflies during the flight period were: H. minuta - 14.8 ± 7.3 sawfly trap-1 in 2010 and 54.2 ± 35.9 sawfly trap-1 in 2011; H. flava - 13.3 ± 5.2 sawfly trap-1 in 2010,and 16.6 ± 6.9 sawfly trap-1 in 2011; and H. testudinea in organic orchard - 38.3 ± 26.2 sawfly trap-1 in 2010 and 5.0 ± 2.8 sawfly trap-1 in 2011, in conventional orchard - 14.8 ± 8.1 sawfly trap-1 in 2010 and 9.3 ± 4.3 sawfly trap-1 in 2011. Conditions for development of both plum sawfly species were better in 2011, when abundance nearly reached the economic threshold. Population density, cumulative trap catches during the flight period, and damage caused by apple sawfly varied significantly between the study years and apple cultivars. In 2010, apple sawfly was more abundant and caused more serious damage than in 2011. The economic threshold of 30-40 individuals per trap was reached in 2010 due to the better conditions of development. The various apple cultivars suffered different damage levels: cv. ‘Aldas’, ‘Vitos’ and ‘Rubinola’ suffered the highest damage in the organic orchard, but no significant differences were observed. In the conventional garden, cv. ‘Auksis’ had the most damaged fruits.