Lleida, Spain
Lleida, Spain

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Torres E.,IRTA Fruitcentre | Recasens I.,University of Lleida | Avila G.,IRTA Mas Badia Field Station | Lordan J.,IRTA Fruitcentre | And 2 more authors.
Scientia Horticulturae | Year: 2017

Fruit mineral analysis at harvest is recommended as a predictive method to assess the risk of bitter pit (BP) in apple orchards, although it only provides valuable information if conducted just before harvest. To gain more time to implement corrective action, some studies proposed early season analysis of fruitlets. However, neither results were reported for analysis accuracy, nor the best time to perform it. The objective of this study was to evaluate the accuracy of early season fruitlet analyses at different stages — 40, 60 and 80 days after full bloom (DAFB) — to predict BP in ‘Golden Smoothee’ apples. Multivariate models for each early stage were developed and compared to a linear model using the calcium (Ca) content alone. Both the multivariate analyses and linear correlations suggested 60 DAFB as the best time to perform early mineral analysis. The Ca concentration in the fruit contributed greatly to BP incidence either at an early stage or at harvest. The boron concentration showed a negative correlation with Ca concentration and a positive correlation with BP incidence. The other tested nutrients (magnesium, nitrogen, potassium) showed little effect on the prediction models and/or an irregular pattern. The accuracy of the multivariate model (R2 = 0.580) was not significantly better than the analysis of Ca alone (R2 = 0.504) when the occurrence of BP was high. Finally, a Ca threshold at 60 DAFB equal to or greater than 11.0 mg 100 g−1 fresh weight (f. w.) indicated a low risk of BP (<10% of incidence). This early season threshold value was a better indicator of the BP risk than the traditional threshold value at harvest (5–6 mg Ca 100 g−1 f. w.). © 2017 Elsevier B.V.


Torres E.,IRTA Fruitcentre | Recasens I.,University of Lleida | Lordan J.,IRTA Fruitcentre | Lordan J.,Cornell University | Alegre S.,IRTA Fruitcentre
Scientia Horticulturae | Year: 2017

Calcium (Ca) sprays and Ca applications to soil throughout the growing season or Ca solution dips at post-harvest are widespread practices to supply Ca and decrease bitter pit in apples. However, published results conflict, and there is no information about the effectiveness of combining all these treatments. In the present study, the following treatments were assessed during four growing seasons: early-season (April) Ca soil applications applied 4 times, mid-season (May) CaCl2 sprays applied 7 or 13 times, late-season (June) CaCl2 sprays applied 7 times, and the combination of late-season sprays and soil applications. In addition, post-harvest dips were evaluated in the latter two growing seasons. Notably high bitter pit incidences were monitored for the first and fourth year of study (>20%), while the second and third year were almost without incidence. Post-harvest dips mitigated bitter pit incidence to a greater extent than pre-harvest treatments, and the sprays mitigated bitter pit to a greater extent than Ca soil applications. The combination of sprays and soil applications did not improve the results relative to Ca sprays alone. No detectable advantage for starting spray programmes earlier than June was observed. Our results showed a trend towards reduced bitter pit with an increasing number of CaCl2 sprays, but this was not clearly an effect of maximizing fruit Ca. Finally, applying 13 CaCl2 sprays in combination with a Ca solution dip at post-harvest appeared to be the most effective practice for minimizing the risk of bitter pit development. © 2017 Elsevier B.V.


Lordan J.,IRTA Fruitcentre | Alegre S.,IRTA Fruitcentre | Gatius F.,IRTA Fruitcentre | Sarasua M.J.,IRTA Fruitcentre | Alins G.,IRTA Fruitcentre
Bulletin of Entomological Research | Year: 2015

A multilateral approach that includes both biotic and climatic data was developed to detect the main variables that affect the ecology and population dynamics of woolly apple aphid Eriosoma lanigerum (Hausmann). Crawlers migrated up and down the trunk mainly from spring to autumn and horizontal migration through the canopy was observed from May to August. Winter temperatures did not kill the canopy colonies, and both canopy and root colonies are the source of reinfestations in Mediterranean areas. Thus, control measures should simultaneously address roots and canopy. European earwigs Forficula auricularia (Linnaeus) were found to reduce the survival of overwintering canopy colonies up to June, and this can allow their later control by the parasitoid Aphelinus mali (Haldeman) from summer to fall. Preliminary models to predict canopy infestations were developed. © Cambridge University Press 2014.


PubMed | IRTA Fruitcentre
Type: Journal Article | Journal: Bulletin of entomological research | Year: 2015

A multilateral approach that includes both biotic and climatic data was developed to detect the main variables that affect the ecology and population dynamics of woolly apple aphid Eriosoma lanigerum (Hausmann). Crawlers migrated up and down the trunk mainly from spring to autumn and horizontal migration through the canopy was observed from May to August. Winter temperatures did not kill the canopy colonies, and both canopy and root colonies are the source of reinfestations in Mediterranean areas. Thus, control measures should simultaneously address roots and canopy. European earwigs Forficula auricularia (Linnaeus) were found to reduce the survival of overwintering canopy colonies up to June, and this can allow their later control by the parasitoid Aphelinus mali (Haldeman) from summer to fall. Preliminary models to predict canopy infestations were developed.

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