engleski

Impact of OAK lace bug Corythucha arcuata (Heteroptera: Tingidae) on Pedunculate OAK (Quercus robur) seed quality

Damages on oak leafs done by alien pest species Corythucha arcuata (Say, 1832) (Heteroptera: Tingidae) are growing every season since it was discovered in Eastern Slavonia Croatia in autumn of 2013. During the five-year period and spread of C. arctuata westward, an urgent need for damage assessment and impact of pedunculate oak seed production and acorn quality forced research focus on this newly established and growing forest pest of oak stands. For the acorns collected in seed orchard ‘Petkovac’ from the onset of internodial clones by phenophases on 07.09.2017., total laboratory germination in sand was 67 %. The rest were abnormal acorns. This research proves that previously collected acorns shows good germination, which is important in case of strong attack of C. arcuata. For the needs of the nursery operation, the earlier fallen acorns can be used. By the flotation we determinated 95 % viability of acorns. The germination energy was 0 % and the first acorns started to germinate 14 day. First results of acorn quality suggested that acorns collected in seed orchard ‘Petkovac’ showed worse quality compared to acorns from seed stand: germination percentage was 55, 9 %, percentage of abnormal seedlings was 12, 5 %, percentage of fresh ungerminated seeds was 5, 0 % , and percentage of dead seeds was 27, 0 %. Portion of abnormal seedlings and fresh ungerminated seeds indicated the impact of Corythuca arcuate on acorn quality. The greatest concern is negative influence of C. arctuata attack on acorn production quality, growth and increment both in oak stands and oak seed orchards and by this on sustainable development goals in Croatian managed forests.

Corythucha arcuata ; invasive alien species ; pedunculate oak ; seed quality ; integrated pest management

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