Effect of organic soil amendment and Trichoderma harzianum on strawberry root rot caused by Phytophthora fragariae under greenhouse conditions

الملخص EN

Phytophthora fragariae has been reported as one of the most important pathogens that cause diseases to strawberry with substantial economical damage to the crop.

One group of micro-organisms that show potential to control diseases induced by Phytophthora spp.

is Trichoderma harzianum.

Application of organic matter has shown to suppress a range of soil-borne diseases.

Therefore, experiments were carried out during 2011 under greenhouse conditions at Rabbah Agricultural Research Station, Mutah University, Jordan to investigate the potential benefits of organic fertilizer (poultry manure: 20 and 40 ton/ha and sheep manure: 20 and 40 ton/ha) and T.

harzianum on severity and incidence of strawberry root rot disease caused by P.

Fragariae.

The results showed that disease severity was significantly increased in soil treatment only and without bio-control.

Disease severity decreased significantly with application of soil amendment and T.

harzianum.

Disease control percentage increased with application of two manure types with T.

harzianum.

Also the percentage highly increased with poultry (20 and 40 kg) and reached 52% and 57% respectively.

Disease percentage reduced significantly with increasing the amount of organic amendment with or without T.

harzianum as compared to soil treatment only.

In soil treatment only with the pathogen, disease percentage reached 70%, while with T.

harzianum it was 53% and it was highly significant.

Soil amendment and T.

harzianum added to soil in all treatments significantly reduced disease percentage.

T.

harzianum added to strawberry seedlings showed highly significant reduction in disease percentage in all treatments.

The results showed that T.

harzianum applied to soil amendment with manure infested with P.

fragariae decreased disease percentage and severity and the best treatment in controlling disease was T.

harzianum and poultry at 40 tons/ha.