Chestnut (Castanea Miller) belongs to beech family (Fagaceae), and has economic value because of its timber and fruit. It has 13 known species spreaded through the mild temperature zone of the Northern Hemisphere. Five of those species are bred on East Asia, seven on North America and one on Europe[2,3]
Turkey as being one of the gene centers of chestnut (Castanea sativa Mill.) takes the third place in the world with its annual production of 50.000 tons after China and South Korea with production of 50.000 tonnes[4,5]. The most important disease of chestnut is chestnut blight (Cryphonectria parasitica (Murill) Barr) causes the loss trees of European (Catanea sativa) and American (C. dentata) chestnut varieties [6-9]. Chestnut blight caused a drop of Turkeys production rate from 90.000 tons in 1990 to 50.000 tons in 2002.Pathogen infects the tree at the wound and cracked areas by means of its ascospores from perithecia and conidia from pycnidium. Slight moist weather conditions are suitable for spreading spors. Yellow or orange-brown pycnidial stroma is formed on shell tissue in advanced stages of infection. Conidia of pathogen are rod shaped and colourless. Perithecia of pathogen are formed in stroma in which pycnidia are formed during vegetation. Both picnidia and perithecia can be seen in a stroma at the same time. Perithecial stroma is usually brown. Necrotic and cancer areas are formed on the cambium and shell tissues of piths of stems and branches due to this disease. Debrises can be formed because of the sudden death of shell tissue and cambium due to this disease. If the death is delayed swellings are seen at diseased areas and cracks at shell tissue. Leaves and shoots lose their vitality in the course of time as the water cannot be spread to the piths of these organs. Pathogen can be carried with wind and rain as well as with grafting materials. Chemical control against the disease is applied even the height of the plant restricts the method[11,12].
In this study, various chemicals and combination which were expected to control the disease were tried on the plants in SamsunTerme province.
MATERIALS AND METHODS
This study was accomplished in chestnut plantation in Terme (Samsun) province
in 2003-2004. The basic material of the research is the grafted seedlings which
belong to chestnut genotypes selected from Sinop and Samsun provinces[13,14].
The grafted seedlings were planted in 1998 and 1999.
|| Application mode of the chemicals
The chemicals used in this research were; Copper oxychlorite (5%), Benomyl
50 WP (60 g/100 L water), Carbendaxim 50 WP 50 WP (75 g/100 L water). The study
was set up according to randomized block design with 6 characters and 3 replications.
The chemicals were applied on 10 and 25 June and 10 July (Table
In the application, the infected areas on the branches and trunk were carved
down to the health tissue. No chemical was applied on the carved areas for the
control. For the applications other than control, Copper oxychloride (5%) was
applied on the carved areas by brush, benomyl and carbendazim were applied on
the leaves by hand pulverizator (Table 1). Application was
repeated 3 times15 day intervals. Counting and evaluation was performed
6 months later than the final application. Evaluation was based on 05
scale considering the size of infected regions. The area of infected regions
was calculated by elliptical calculation method
||Elliptical blight area,
||Length of elliptical blight and
||Width of elliptical blight
The 0-5 scale was formed as follows;
||No blight formation on branches and/or trunk
||1-5 cm2 lesion on branches and/or trunk
||6-10 cm2 lesion with cracks on branches and/or trunk
||11-20 cm2 lesion with cracks on branches and/or trunk
||21-30 cm2 lesion with small number of perithecium and cracks
on branches and/or trunk
||Lesion greater than 30 cm2 in area with denser number of perithecium
and cracks and/or dry up
The rate of disease was calculated by using Towsend-Heuberger formula on these
|| The rate of disease,
||Number of plants,
||Maximum scale value and;
||Total number of plants
The influence rate of chemicals was calculated by using the disease rate results
and Abbot formula:
I%: Influence rate of chemical,
Dcon: Disease rate on Control,
Dch: Disease rate on chemical application.
Angle transformation (arc Sin) transformation is applied to the calculated average rate values to realize the differences between the groups. The lettering in the tables was done per transformed figures. MSTAT-C program was utilized in the evaluation of data. Duncan Multiple Range Test in MSTAT-C program was used to find out the real important differences between the average valves and to mark the different ones with different letter.
Six months after the application of chemicals the results were evaluated and the rate of disease (%) and the influence rate of chemicals (%) are given in Table 2 and 3, respectively.
Research proves that the rate of disease shows considerable difference depending on the pattern of the application of chemicals. The highest disease rate was found on the control application and the lowest the disease rate is on the Copper oxychloride+Carbendazim combination (Table 2).
|| Rate of disease (%) corresponding to chemical application
|Means followed by the same letter are not significantly different
at P≤ 0.01
|| The influence rate of chemicals (%)
|Means followed by the same letter are not significantly different
at P≤ 0.05
Results show considerable differences in average rate of influence depending on the application of chemicals. The most effective combination was found as Copper oxychloride+Carbendazim and Copper oxychloride+Benomyl combinations. The difference of influence between Copper oxychloride, Benomyl and Carbendazim was not (Table 3).
The development of disease in control mode is greater than the chemical applied
modes by the level of 0.05 and 0.01 in the average values. The combinations
of Copper oxychloride+Carbendazim and Copper oxychloride+Benomyl provide best
results considering both the disease development rate and chemical influence
rate criteria. These decisions approve the results of a research done to determine
the effects of various carbendazim concentrations on C. parasitica infections
for various grafting methods.
In the research, 0.5, 1 and 2% carbendazim concentrations were applied to the grafting locations for mechanical cleft, whipand bark grafting and T and ring budding methods, carbendazim was effective against canker disease, but at the highest concentrations reduced the percentage of successful grafts primarily on bark and T-budding grafts.
In another research in which some fungusits were added to the chemicals, it was found out that the effect of carbendazim was enhanced if mineral oil or Siapton L10 was added. This is also in parallel with our research. Present Study proves that the simultaneous application of chemicals on both green parts and branches-trunk is more effective however, since the green part application is not possible for high trees, the simultaneous application is limited for the bushes only and this is a restriction. The post-application infections are not controlled by the method described in research and this is another disadvantage. Nevertheless, the method described in the research slows down the development of the disease in trees and the bushes and could be regarded as a success.