Environmental conditions for Diaphorina citri Kuwayama (Hemiptera: Liviidae) take‐off

Abstract

Environmental factors that influence flight activity of Diaphorina citri Kuwayama (Hemiptera: Liviidae) may have implications for Huanglongbing spread and management. In this work, four studies were conducted to evaluate the effect of environmental conditions on D. citri take‐off. In the first, insects were transferred to sweet orange seedlings and confined inside an acrylic cage to verify the take‐off periodicity and the effect of environmental factors on this process. In the second, take‐off temperature threshold was estimated by recording the number of insects that initiated flight from a platform when subjected to gradual temperature increases from 15 to 39°C. In the other studies, we evaluated the effect of different photoperiods and temperature regimes (third study) and of constant temperatures (fourth study) on the propensity for D. citri flight. Insects were confined in clear plastic bottle cages with tubes of 50 ml placed on the cab, to collect emerged adults that initiated flights. Results showed that a small portion of the tested population (maximum 10%) tends to take off from plants and this behaviour is more prevalent in the afternoon (14:00–16:00 h), coinciding with daytimes of lower humidity and higher thermal amplitude. Adults that were submitted to lower temperatures (18°C) and short light periods (10 h) showed less propensity to flight. In contrast, at constant 27°C, the insects were more prone to flight, and this result was confirmed when individuals were submitted to increases in temperature, indicating that 27.14°C is the take‐off temperature threshold of D. citri. Results show that temperature plays an important role in the flight activity of D. citri and suggest that control measures of the insect may be more effective in the morning and in temperatures below 27°C, when the probability to take off from a host is lower.

Processed kaolin affects the probing and settling behavior of Diaphorina citri (Hemiptera: Lividae)

“…In the field, the seedlings with marked psyllids were pruned and placed on 1.5‐m‐tall release platforms located on the east side of the area and at 6.5 m from the central part of each plot (Figure ). Psyllid releases were performed in the afternoon (∼ 15:00 h), which is the period of highest D. citri flight activity . Furthermore, the environmental conditions (temperature and rainfall) were monitored using a weather station (Vantage Pro2 6152; Davis Instruments, Hayward, CA, USA) located at 20 m from the experimental area.…”

“…Psyllid releases were performed in the afternoon (∼ 15:00 h), which is the period of highest D. citri flight activity. 9,41,42 Furthermore, the environmental conditions (temperature and rainfall) were monitored using a weather station (Vantage Pro2 6152; Davis Instruments, Hayward, CA, USA) located at 20 m from the experimental area.…”

Caracterização da movimentação de psilídeos (Hemiptera: Psylloidea) no contexto da disseminação primária do Huanglongbing dos citros

“…A correlação positiva entre psilídeos capturados nas diferentes alturas (2,5 m e 7,5 m) permite inferir que os indivíduos estiveram sujeitos a processos de ascensão vertical que provavelmente foram auxiliados pelos fenômenos físicos das massas de ar nas diferentes camadas da atmosfera, de acordo com análises de movimentação vertical em outros hemípteros e outras ordens de insetos analisados por Taylor (1974), McLean et al (1986, Dingle (1996) e Reynolds et al (2006). (Sales, 2015;Tomaseto et al, 2017).…”

“…No caso de D. citri, sabe-se que a habilidade de voo é limitada, sendo que a capacidade máxima de voo é de aproximadamente 1200 m, comprovada mediante experimentos em câmaras de voo (Arakawa & Miyamoto, 2007 (Sétamou et al, 2012), pressão barométrica e temperatura (Martini & Stelinski, 2017;Tomaseto et al, 2017), umidade relativa (Hall & Hentz, 2011), além dos ritmos circadianos (Sétamou et al, 2012). Dentro dos fatores bióticos mais comumente relacionados com a decolagem se encontra a presença de brotos das plantas hospedeiras (Kobori et al, 2011)…”

Spatial distribution and temporal progress of >i<Huanglongbing>/i< in areas with strict disease management

“…Therefore, for successful HLB management, the removal of symptomatic trees and psyllid control must be accomplished regionally by citrus growers, and include residential citrus and abandoned orchards (Bassanezi et al, 2013;. However, an area-wide management is not simple to accomplish due the difficulty for coordinating control actions among neighboring farmers and government regulation is required Tomaseto et al, 2017). Seeking to facilitate an area-wide coordinate management, programs developed by Fundecitrus, such as the "Phytosanitary Warning System" and the "United Against Greening" campaign have been assisting citrus growers.…”