The use of the cumulative degree-days to predict olive fly, Bactrocera oleae (Rossi), activity in traditional olive groves from the northeast of Portugal

Abstract

Terra Quente, situated in the province of Trás-os-Montes (northeast of Portugal), is one of the most important olive growing areas of Portugal. In this region, which is extremely hot and dry during summer, losses due to the olive fly, Bactrocera oleae (Rossi), are highly variable between years, with estimates ranging from 16.3 to 98.8% of infested fruits. The objective of this study was to test the use of the degree-days models, based in a daily accumulation of temperature (°DD) to predict insect activity in the field and timing control measures, in such a climatic condition. Seasonal flight activity periods and insect development were studied from 2005 to 2008 in traditional olive groves and a degree-day model was developed for predicting the development of olive fly second generation, which is the one that can cause losses. It was found that, while the use of these models could be hampered by high temperatures and low relative humidity prevailing during summer, they may have some potential as a tool for the management of B. oleae populations, allowing the identification with acceptable error of the main second generation events. Results indicated that, if adulticide sprays are to be used, the spraywindow for their applications lasts between an accumulation, since January 1, of 1837.20 ± 35.82°DD 8.99 , which corresponds to the beginning of the insect second flight and 2045.87 ± 34.30°DD 8.99 , which corresponds to its main peak.

Olive Landscape Affects Bactrocera oleae Abundance, Movement and Infestation

“…H3: Scrublands are also suitable for B. oleae, acting as a summer refuge for the flies and thus as a source of infestation for olive groves. H2 and H3 were raised because of the known drastic decrease in B. oleae abundance in olive groves in summer [20][21][22][23]. Cost values were assigned to the different land uses according to these hypotheses (Table 1).…”

Application of Accumula ted Heat Units in The Control of The Olive Moth, Prays Oleae (BERN.) (LEP., PRAYDIDAE), in Olive Groves in Southern Spain

“…For the practical determination of the optimal dates for the application of control treatments, January 1 has been established as the starting point for the accumulation of degree-days, as indicated by Touzeau (1981), Castro et al (2008), Armendariz, et al (2010, Gonçalves and Torres (2011) and Canales et al (2014).…”

“…Among the factors that determine the development of insects, temperature plays a primordial role (ALDANA, 1983) in determining the speed of enzymatic reactions that regulate the metabolic activity of organisms. The influence of temperature on biochemical processes (especially in poikilothermic organisms) has led many researchers to adopt prediction tools to estimate the duration of insect development phases based on the knowledge of their relationship with ambient temperature (WAGNER et al, 1984;PITZALIS et al, 1985;BELCARI et al, 1989;FAN et al, 1992;COUTINHO et al, 1997;BRÉVAULT;QUILICI, 2000;ASPLANATO;FARCÍA-MARÍ, 2001;GALLARDO et al, 2009;GONÇALVES;TORRES, 2011;HAAVIK et al, 2013;PETACCHI et al, 2015). Insect development takes place exclusively within a relatively narrow temperature range and is determined by two temperature threshold values:…”

Climate Change and Major Pests of Mediterranean Olive Orchards: Are We Ready to Face the Global Heating?

“…Furthermore, during summer 2014, temperatures rarely overpassed the thermic threshold of 35 • C. In this context, adult physiological activities remained undamaged, and great consequences on olive yield were reported [40]. The CDD model has also been used in northeast Portugal to predict the second generation of B. oleae, the most threatening in the Trás-os-Montes region, using data from 2005 to 2008 [62]. The model was suitable for predicting in advance B. oleae infestation both in 2006 and 2008.…”

“…The model was suitable for predicting in advance B. oleae infestation both in 2006 and 2008. In 2007, the same model was not so efficient, probably in consequence of abnormal low summer temperatures (average 20.7 °C) [ 62 ]. Despite this unusual condition, the model was demonstrated to be a potential tool for B. oleae management, allowing the prior identification of the second-generation activity and consequently the estimation of the infestation risk [ 62 ].…”