The study was conducted under greenhouse artificial infection and natural infection in the field with Fusarium oxysporum f.sp. melonis. the causal organism of muskmelon Fusarium wilt to compare the effect of 3 antagonistic fungi, Trichoderma harzianum. Chaetomium elobosum and Gliocladium penicilloids as biological agents and 3 fungicides (Bavistin 50, Topsin M70 and Rovral 50) on muskmelon cultivars (El-Shahd and Ananas). Under greenhouse conditions, treating seeds with the antagonistic fungi, especially T. harzianum. was as effective as fungicides especially Bavistin 50 and Topsin M70, which increased the percentage of healthy survival plants and plant growth. Under field conditions, treatment with antagonistic fungi and fungicides increased percentage of healthy survival plants. Meanwhile, T. harzianum or Bavistin 50 exhibited the highest number of marketable fruits and fruit yield. Reducing, as well as total sugars were generally higher in the roots of plants that resulted from antagonistic fungi treatments as well as fungicides treatments. Total phenols were higher in roots of El-Shahd cv compared with Ananas cv whether planted in infested or uninfested soils. Treating seeds with the antagonistic fungi C. globosum, T. harzianum or with fungicides increased free and total phenols content in the plant roots. Total free amino acids in roots were higher in the Ananas cv than El-Shahd cv. Soil infestation with F. oxvsporum f. sp. melonis decreased amino acids in roots. Treating seeds with antagonistic fungi or fungicides increased total free ambo acids. |