Chestnut breeding for resistance to root rot/ ink disease

Submitted by alexandrac on 22 June 2020
Improved chestnut clones

European chestnut has a great economic impact in the rural economy of mountainous regions of southwest Europe. The main threats for this important crop are pests and diseases, being the most important root rot, blight disease and gall wasp. Root rot, caused by Phytophthora cinamomi (Pc), is the most severe disease which impact negatively the production of chestnut orchards, which are important for its edible nuts.

The main objective is to release a new product to the market: new genotypes with improved resistance to Pc, selected from the breeding program on course, to be...

The chestnut gall wasp in the Portuguese region of Terra Fria Transmontana: Three years of biological control

Submitted by joanaap on 12 June 2020
Most recent biological control action, carried out by the Agro-Forestry Association ARBOREA in partnership with several regional entities (IPB / CNCFS, PRORURIS, CM Vinhais and Parish Councils) (1) Parasitoid packaging (2) Parasitoid release in affected chestnut (3) Torymus sinensis after release (ARBOREA)

The Dryocosmus kuriphilus insect, chestnut gall wasp, introduced in Portugal in 2014, represents a serious threat to the national production of chestnuts. Over the years, various pest outbreaks have been identified, which is currently present in much of the Terra Fria Transmontana region, with levels of severe infestation levels. The official reports state, “We are currently witnessing a large and rapid dispersion of the insect and the alarm of the populations, given the damage it is already causing, so, an intensification of the parasitoid releases for these regions should be...

Post-fire presence and dynamics of xylophagous insects on cork oak ecosystems

Submitted by joanaap on 9 June 2020
Montado landscape after fire (Grândola, 2017).

Cork oak ecosystems have been experiencing a serious decline in the last decades attributed to different causes, including wildfires. After fire trees may become particularly vulnerable to forest pests, which may further affect the vigor of surviving trees and give rise to massive dispersing offspring affecting surrounding areas, but this was rarely assessed in Mediterranean oak ecosystems. Thus, the objective of this study was to assess the presence and dynamics of xylophagous insects on cork oak forests following fire in central Portugal.

Classical biological control of the chestnut gall wasp Dryocosmus kuriphilus in France

Submitted by Haimad Baudrill... on 13 May 2020
Distribution map of the Torymus sinensis experimental releases done between 2011 and 2014 in continental France and Corsica (rescaled in box). Red circles, 1x100 females released; green circles, 2x50 females released; blue circles, 1x1 000 females released; purple circles, 2x110 females released

The objective of the project was to implement in France a classical biological program against the chestnut gall wasp, Dryocosmus kuriphilus (Dk), using releases of the exotic parasitoid Torymus sinensis. The expected outcome of this project were (i) the permanent establishment of the parasitoid and (ii) an efficient and long-term control of the pest.

Regulation of chestnut blight by hypovirulent strains

Submitted by Haimad Baudrill... on 5 May 2020
Symptoms of chestnut blight caused by: (1) non-virus-infected strains of Cryphonectria parasitica. (2) by virus-infected strains of Cryphonectria parasitica "hypovirulent" strains

A method is resented to reduce the severity of cankers caused by chestnut blight,  Cryphonectria parasitica. This pathogenic fungus penetrates and necroses cortical tissues, which provoke mortality of adult trees aerial parts and failure of grafting.

In the 1970s, French researchers developed a biological control method using hypovirulent strains of the fungus. Since then, a research programme at INRA conducted with several organisations (Chambers of Agriculture, Union of Chestnut production Associations, the Forest Health Department) aims at clarifying and improving...

Participatory selection of hardy and ink-disease resistant European chestnut trees

Submitted by Haimad Baudrill... on 5 May 2020
Ink disease resistance test on cuttings of chestnut stems

The objectives of this participative research program are:

1: Select surviving European chestnut trees within strong impacted areas by the ink disease

2: Evaluate their resistance against Phytophthora in laboratory, and verify their belonging to sweet chestnut, the species Castanea sativa.

3: Use the individuals showing the best resistance capacities against ink disease (“elite trees”) as seeds producers in seed orchards.

The expected results are:

- Reconquest and renewal of the actually declining chestnut orchards

- Decrease of...

Evaluation of susceptibility to Dryocosmus kuriphilus (Hymenoptera: Cynipidae) in Castanea sativa and in hybrid cultivars

Submitted by Roberto Rubio on 9 January 2020
Dryocosmus kuriphilus - chestnut gallwasp

The aim is to determine different levels of sensitivity of different cultivars to the  chestnut gall wasp. Among the cultivars that have been evaluated are interspecific hybrids and traditional European cultivars.