Nematicidal activity of the leaf powder, leaf extracts and formulated leaf extracts of Myrtus communis, an evergreen shrub that is widely distributed in Israel and other Mediterranean countries, was evaluated using the root‐knot nematode Meloidogyne javanica in in vitro and pot experiments. Leaf powder added to sand at 0·1% (w/w) reduced the number of juveniles recovered from the sand by more than 50%. Reduction in galling index and number of nematode eggs on tomato roots was also observed by incorporating the leaf powder at 0·1–0·4% (w/w) in the soil in pot experiments. Leaf powder extracts with methanol or ethanol showed the highest nematicidal activity among all extracts tested. Emulsifiable concentrates of leaf‐paste extract at a concentration as low as 0·005% (a.i., w/w) reduced the number of juveniles recovered from treated sand and the gall index of cucumber seedlings. The extract paste at 26 g m−2 was also effective in reducing the gall index of tomato plants in field‐plot experiments. The leaf powder at 0·2% and the formulated leaf‐paste extract at 0·02% were also nematicidal to Tylenchulus semipenetrans and Ditylenchus dipsaci, but not to Pratylenchus penetrans or Steinernema feltiae. At least three nematicidal compounds were found in the leaf extract upon fractionation by thin‐layer chromatography. The results suggest that the leaf powder and paste extract of M. communis are potential nematicides against root‐knot nematodes.

A reliable, rapid and low-cost screening bioassay, based on measuring lesion sizes, rotten tissue weight and tissue colonization 1 week after the injection of a conidial suspension into the stem scars of mature green tomato fruits, was developed to assess the aggressiveness of Colletotrichum coccodes isolates. This protocol was compared with inoculation of either potato plantlets from in vitro multiplication, or ripe tomato fruits, using C. coccodes isolates from potato and from tomato. Aggressiveness to mature green tomato fruits was scored by measuring lesion size and weight at the scar end of the fruit, while colonization was measured in samples taken from the blossom end. Values of all three disease parameters were significantly higher (ca. 3 times) with aggressive isolates of the pathogen than with less aggressive ones. High correlation levels among these three parameters were obtained. Also, the aggressiveness to mature green tomatoes was highly correlated with the aggressiveness to potato tissue culture plantlets. It was concluded that lesion size in inoculated tomatoes can be used as a sole measure for estimating the aggressiveness of C. coccodes isolates to either tomato or potato.

Inula viscosa is a perennial plant native to the Mediterranean Basin. Extracts made from the shoots of this plant exhibited a strong fungicidal activity in vitro and in vivo. TLC analyses revealed at least 7 fungicidal compounds. Most are lipophilic. When such extracts were sprayed on the leaf surface of crop plants they effectively controlled downy mildew in grape, cucumber and tobacco; late blight in potato and tomato; gray mold in cucumber and tomato; and, powdery mildew in cucurbits and cereals. Field experiments conducted with grape vine and potato resulted in effective control of Plasmopara viticola and Phytophthora infestans, respectively. The data suggest that Inula viscosa is a useful source of herbal fungicidal preparations for agricultural use.