First record, new cultivated host and host plant preference of the invasive oak lace bug (Corythucha arcuata Say, 1832) (Heteroptera: Tingidae) in Transcarpathia (West Ukraine)

Oak lace bug (Corythucha arcuata) has continuously spread through Europe since its appearance in 2000, and it has become a dangerous pest of Quercus species in most countries. Despite of its high abundance in the surrounding countries it was found in West Ukraine only in 2020. During our investigation carried out in 2020 OLB was detected in all studied large forest patches of the Ukrainian part of the Carpathian Lowland. These were one of the newest distribution data from Ukraine after its appearance in the far coast of Black See near Yalta (South Ukraine). OLB most live on Q. robur and Q. petraea but in an orchard located near an infested forest patch we found infested sweet cherry (P. avium) trees, which is a new, formerly not mentioned cultivated host of the pest.

Corythucha arcuata (Say, 1832) (Hemiptera, Tingidae) in its invasive range in Europe: perception, knowledge and willingness to act in foresters and citizens

The oak lace bug (OLB) Corythucha arcuata (Say, 1832) is an invasive alien species (IAS) that potentially could have many negative impacts on European oak health. Certain measures can be applied to counteract these effects. However, these measures may not be acceptable for forest managers or other stakeholder groups, such as private forest owners, environmental NGOs or the general public. Thereby, we set out to study the perception and knowledge of foresters and other stakeholders on the health status of European oak forests affected by oak lace bug and to investigate what forest health management measures would be acceptable to these target groups. An online survey questionnaire was designed and distributed via social networks, as well as professional networks via e-mails. The survey questionnaire was completed by 2084 respondents from nine European countries: Austria, Croatia, Belgium, France, Hungary, Italy, Romania, Serbia and Slovenia. Even though only a little over 60% of respondents reported they had noticed the discolouration of oak leaves caused by OLB, almost all (93%) considered it to be a problem. As respondents come from a country where C. arcuata is widespread and established, people’s general knowledge and awareness of OLB began to increase. The survey revealed that foresters thought that the insect affected photosynthesis, acorn crop and the aesthetics of the trees, but cannot cause death of trees. However, they assume that the value of the wood would decrease (this fact is also supported by the respondents who are connected to an environmental NGO), but that OLB does not affect property value. However, forest owners claim that the value of the property can be affected and that people would avoid entering the forest. In terms of potential control methods, respondents preferred biological or mechanical measures over chemical ones. We consider this study to be a good basis for further research on the topic of perception, knowledge and attitudes related to OLB since we can expect that the IAS, such as OLB, will certainly spread to European countries that were not included in this survey.

Short Communication: First record of the cassava lace bug Vatiga illudens (Drake, 1922) (Hemiptera: Heteroptera: Tingidae) from East Java, Indonesia

Puspitarini RD, Fernando I, Setiawan Y, Anggraini D, Rizqi HA. 2021. Short Communication: First record of the cassava lace bug Vatiga illudens (Drake, 1922) (Hemiptera: Heteroptera: Tingidae) from East Java, Indonesia. Biodiversitas 22: 2870-2876. The cassava lace bug, Vatiga illudens (Drake, 1922) (Hemiptera: Heteroptera: Tingidae) is recorded from Indonesia for the first time. This species is found on the abaxial surface of leaves of cassava (Manihot esculenta Crantz, Euphorbiaceae) in several plantations of East Java and heavily infest this plant. Vatiga illudens is native to the Neotropical Region and seems to be the alien species in the Oriental Region. This tingid has already spread over a wide region of East Java, suggesting that the invasion of the lace bug endangers the other regions cultivating cassava.

Chemical Control of Corythucha arcuata (Say, 1832), an Invasive Alien Species, in Oak Forests

In addition to the classic biotic and abiotic factors that have disrupted the health of forests throughout history, lately, the balance of forest ecosystems has been disturbed by different phenomena such as climate change, pollution, and, especially, biological invasions of invasive alien species. One of the alien species that has invaded Europe relatively quickly is an insect species of North American origin, the oak lace bug (Corythucha arcuata Say, 1832 Heteroptera: Tingidae). In the context of the rapid spread of infestations and the severity of attacks on oak trees in infested forests, this paper aims to assess measures to manage this species in the future. Namely, the effect of aerial chemical treatments on oak lace bug has been investigated with two influencing factors: the mode of insecticide action (contact and systemic) and the treatment volume (low volume and ultra-low volume). The experiment was conducted in two forests over a total area of 350 hectares. The results show that the reduction of the nymph population varied from 91% to 96%. However, the residual population was sufficient to allow differentiated re-infestations over time, more quickly after contact insecticide sprays (22 days after treatment) and slowly after systemic insecticide sprays (more than a month after treatment). This re-infestation time difference had implications on attack intensity as well, with stronger leaf discoloration observed in areas treated with a contact insecticide compared with those treated with a systemic insecticide.

Overwintering mortality of the oak lace bug (Corythucha arcuata) in Hungary – a field survey

The North American oak lace bug (Corythucha arcuata) was first discovered in Europe (Norhern Italy) in 2000. It started a rapid area expansion in the last decade and has been reported in 20 countries so far. Almost all European oaks are suitable hosts. On top of the host availability, abiotic factors like weather/climate may also have a decisive impact on its further spread and future outbreaks. We conducted a simple field survey within three years, at five locations to estimate the overwintering mortality of the species. Our results suggest that not even a relatively harsh winter (as 2016/2017) caused severe mortality in the overwintering populations. The average mortality of the nine year/location combinations was 30.6% (range 9.1–58.5%). Based on this, the low winter temperature is unlikely to restrict its further spread, therefore continuing area expansion can be predicted.