In this study, the effect of early latent infection caused by Monilina spp. on harvest and postharvest brown rot of sour cherry and peach was investigated. Two field experiments were performed in commercial orchards located at Eperjeske on sour cherry and at Siófok on peach in 2013 and 2014 in order to study the possible relationship between the incidence of early latent infection caused by Monilinia spp. and the incidence of harvest and postharvest brown rot. No latent infection was recorded at popcorn phanological stage of the trees at both locations. The maximum incidence was detected during the pit hardening period. There was a positive correlation between the incidence of latent infection and harvest or postharvest brown rot. The average incidence of latent infection during the crop season explained approximatelly 20% of the total variation in the incidence of postharvest brown rot.
A decline, a slow or sudden decay of vine trunks can occur in any phase of trunk life. In senescent or old plantages the increase in trunk decay is quite common but it is unacceptable in young plantage in their best production years.All over the world as well as in Hungary, a drastic decay of young trunks in nurseries and new plantages have caused panic in the past decades. From among the numerous fungal pathogens which are responsible for considerable financial and yield losses and threaten stock vigour Petri disease, esca and Black foot are the most important. In young decaying plants the fungal species Phaeomoniella chlamydospora, Phaeoacremonium spp. and Cylindrocarpon spp. were the most frequent while other fungi causing different trunk diseases, cancer or decay, like Eutypa lata, Botryosphaeria spp. and Fomitiporia mediterranea were also found. The most important infection source is the infected propagation material. Infection is systematic, the disease process is latent, diseased plants cannot be cured, thus, prevention is the only answer to the challenge.
The aim of the Hungarian apple breeding program started in the Department of Fruit Science was to find resistant apple cultivars against major diseases (scab, powdery mildew, fire blight). The outbreak of fire blight (Erwinia amylovora) in 1996 motivated us to search new resistant sources principally from old traditional apple cultivars. First of all, cultivars have been gathered since 1997 from Carpathia (Visk) and evaluated between 2001 and 2003. In this recent study evaluation of resistance of old Hungarian genotypes to fire blight collected from the English National Fruit Collection (Brogdale, Faversham) is presented.
13 old Hungarian apple cultivars in 2002, and 38 genotypes in 2005 have been evaluated. We used `Idared' and 'Jonathan M41' as susceptible controls and 'Liberty' and 'Remo' as resistant ones. Shoots of two-year-old potted plants were inoculated with a mixture of virulent E. amylovora isolates (Ea2, Ea60, Ea67) at a concentration of 5 x 108 cells/ml. Resistance of apple cultivars was evaluated weekly, four times after inoculation by disease severity of symptoms. Numbers of bacterial colonies in 1 cm length shoot were determined in the fourth week after infection.
8 cultivars in 2002 and 9 cultivars in 2005 displayed notable resistance to fire blight based on one-year data. Based on the coincident data of both years, out of the cultivars collected also from Carpathia ‘Pónyik', and `Sikulai' were found to be resistant and gene sources additional old Hungarian valuable apple genotypes could be selected: `Szabadkai szercsika' and `Tordai piros !davit'. The cultivar `Szemes alma' originated from Visk has proved to be recurrently resistant.
The number of bacterial cells in shoots of the investigated cultivars correlated with the severity of symptoms. With this method, which was introduced by us earlier, we can screen cultivars displaying weak visible symptoms, which cannot be proposed as a source of resistance because of their latent infection.