Fusarium oxysporum schlecht. in Israel

Out of 208 isolates ofF. oxysporum, 158 produced toxic reactions when applied to rabbit skin. This fungus, ubiquitous in the soils of Israel, was the most prevalent component of theFusarium flora in the unirrigated (but not in the irrigated) soils sampled.F. oxysporum var.redolens was common only on unfertilized plots of heavy, unirrigated soils.F. oxysporum was a major constituent of theFusarium flora isolated from most of the 450 samples of 20 field and garden crops, but less common in 98 samples of citrus, avocado and mango fruits. It ranks among the most destructive pathogens of cucurbits (exceptCucurbita pepo), tomatoes, onions, and gladioli in Israel, but causes almost no damage to Brassicae, peas or cotton. In pathogenicity tests with 207 isolates from nine field and two fruit crops, numerous isolates caused seedling mortality, with watermelon, onion, cucumber, tomato and eggplant being the most susceptible. Spore measurements on 160 isolates from plants and 355 from soils, showed that spore size was not markedly affected by plant source or by irrigation, but did differ between soil samples taken at 5 and 20 cm depth, and from manured or unfertilized soils.     

Observations on the fungusEntomophthora culicis in Israel

The fungusEntomophthora culicis (Braun) Fies. 1858 was found in Israel for the first time in 1976 on insects of the order Diptera on grapefruit.     

Occurrence ofFusarium oxysporum F.SP.Melonis race 1,2 on muskmelon in Israel

Fusarium oxysporum f.sp.melonis race 1,2 was isolated from wilted muskmelon plants from two sites in Israel. The isolates caused disease in all the Israeli and French differential cultivars tested, regardless of whether they were susceptible or carrying resistance genesFom 1 orFom 2. This is the first record ofF.o. f.sp.melonis race 1,2 in Israel.     

Relative effects of Alternaria alternata and A. macrospora on cotton crops in Israel

In large commercial fields, the ratio of Alternaria macrospora to A. alternata lesions was 1:0-4 in cv. Pima and 1:19 in cv. Acala. The frequency of A. alternata on Pima and of A. macrospora on Acala increased in an experimental field with mixed Pima and Acala plots. In both cultivars disease was inhibited by fungicidal treatment and by removal of flowers. For all parameters measured (leaf area, number of leaves, flowers and bolls, and yield), the responses to treatments were greater in Pima than in Acala.