تأثير خلات حمض الصفصاف في إنبات أبواغ بعض الفطور الممرضة للنبات، و تقدير كفاءته في مكافحة مرض تعفن أوراق البندورة الطماطم المتسبب عن الفطر Cladosporium fulvum Cooke تحت ظروف البيت االزجاجي

الملخص EN

The effectiveness of seven concentrations (0.003, 0.03, 0.3, 1.5, 3, 8 and 10 mg a.

i.

/ ml) of acetylsalicylic acid (ASA), and four exposure periods (30 minutes, 24 hours, 48 hours and 6 days) on the radial growth of some plant pathogenic fungi on PDA medium under laboratory conditions were evaluated at GCSAR in Damascus, Syria.

Results revealed that the mycelial growth of the following tested fungi: F.

oxysporum f.

sp.

nivum (causal agent of watermelon wilt), F.

oxysporum f.

sp.

melonis (causal agent of muskmelon wilt), R.

solani (causal agent of pepper stem and root rot) and V.

dahliae (causal agent of olive wilt) could be completely inhibited, as a result of the treatment of their conidia/or mycelial agar discs of the fungus R.

solani used in culture, each separately, with aqueous suspensions of ASA at the concentration of 1.5 mg/ml or higher, for 30 minutes or more.

Growth inhibition of the fungus A.

solani (causal agent of potato early blight) on the same medium required the treatment of its conidia with a concentration of 3 mg/ml or higher, for 30 minutes or more, or with a concentration of 1.5 mg/ml for 24 hours or more.

The growth of the fungus C.

fulvum (causal agent of tomato leaf mold) on the medium itself was completely inhibited, when its conidia were treated with a concentration of 3 mg/ml for 24 hours or more, or with a concentration of 1.5 mg/ml, but for a period of 6 days.

The conidia of the fungus V.

dahliae completely lost their ability to germinate, when its conidia were treated by ASA at concentration 0.3 mg/ml or higher, for a period of 24.5 hours.

The conidia germination of the fungi F.

oxysporum f.

sp.

niveum, F.

oxysporum f.

sp.

melonis and A.

solani was completely inhibited by the treatment of their conidia, each separately, with a concentration of 1.5 mg/ml or higher, for the same period, while the inhibition of conidia germination of the fungus C.

fulvum required the treatment of their conidia with a concentration of 3 mg/ml or higher.

Disease severity index value of leaf mold disease on tomato plants "Magic variety" (highly susceptible to the disease) reached 12.8%, when using ASA at 1.5 mg/ml concentration as preventative spraying (3 times, one day interval), and then spraying the plants itself with pathogenic fungus inoculum on the fourth day, and 18.6% in the case of therapeutic spraying (already infected plants with pathogenic fungus was sprayed with the concentration itself of ASA at the onset of appearance of disease symptoms) in the greenhouse experiment, while disease severity index reached 44.5% on the infected control plants, and 21.2% in the treatment of comparative fungicide iminoctadine tris.

These results confirmed the possibility of using ASA in the integrated control program of the leaf mold disease on tomato plants in protected agriculture.