The effectiveness of soil solarization with black (BPE) and clear polyethylene mulches (CPE), 0.04 and 0.06 mm thick, respectively, was tested during the 1986 to 1990 growing seasons for controlling Egyptian broomrape, hemp broomrape and nodding broomrape in heavily infested fields. Solarization for 6 wk reduced or eliminated broomrape infestation and improved crop yields. The CPE started to show splitting and deterioration after 4 to 5 wk of solarization. The BPE lasted in usable conditions throughout the growing season. Deep soil tillage with the hand hoe, after solarization, caused broomrape to reappear. Crops grew best in plots after solarization with BPE if they were planted through the same mulch after it was perforated. Soil solarization with BPE or CPE in large tomato field trials, completely eliminated both nodding and hemp broomrapes during the growing season. However, greenhouse pot experiments indicated that solarization significantly reduced weed seedling numbers, but did not significantly reduce the dry weights of the broomrape plants that emerged in the soil samples taken from solarized plots.
