Phelipanche aegyptiaca (Orobanchaceae) is a parasitic weed that causes severe yield losses in field crops around the world. After establishing vascular connections to the host plant roots, P. aegyptiaca becomes a major sink that draws nutrients, minerals, and water from the host, resulting in extensive crop damage. One of the most effective ways to manage P. aegyptiaca infestations is through the use of herbicides. Our main objective was to optimize the dose and application protocol of herbicides that effectively control P. aegyptiaca but do not damage the cabbage crop. The interactions between the cabbage roots and the parasite were first examined in a hydroponic system to investigate the effect of herbicides on initial parasitism stages, e.g., germination, attachment, and tubercles production. Thereafter, the efficacy of glyphosate and ethametsulfuron-methyl in controlling P. aegyptiaca was examined in five cabbage fields naturally infested with P. aegyptiaca. The herbicides glyphosate and ethametsulfuron-methyl were applied on cabbage foliage and in the soil solution, both before and after the parasite had attached to the host roots. A hormesis effect was observed when glyphosate was applied at a dose of 36 g ae ha⁻¹ in a non-infested P. aegyptiaca field. Three sequential herbicide applications (21, 35, and 49 days after planting) effectively controlled P. aegyptiaca without damaging the cabbages at a dose of 72 g ae ha⁻¹ for glyphosate and at all the examined doses for ethametsulfuron-methyl. Parasite control with ethametsulfuron-methyl was also effective when overhead irrigation was applied after the herbicide application.

Trianthema portulacastrum L. (Aizoaceae), commonly known as desert horse purslane or black pigweed, is a C4 dicot succulent annual herb that is widespread in Southeast Asia, tropical America, Africa, and Australia. In Israel, it is an invasive weed of increasing importance in agricultural fields. The aim of this study was to investigate the biology of this invasive weed and its spread in the Hula Valley of Israel. Initial studies included the investigation of the T. portulacastrum specimens held at the Israel National Herbarium. On-site surveillance for the identification of weed infestation locations was conducted in the Hula Valley throughout 2019–2022, and an infestation map was assembled. In a study of the plant biology, greenhouse pot experiments revealed that T. portulacastrum seeds emerge best from the upper soil levels, and as seed depth increases, the emergence rate decreases, so that at 6 cm soil depth, there was no emergence. In controlled-environment growth chamber studies, there were no significant differences in germination with or without light. A maximum germination of 81% was observed for a 12 h night/day of 25/35 °C regime. Germination rates decreased with the decrease in temperature. A seed germination thermal time model that was developed for estimating the minimum temperature required for germination (T_base) computed this temperature to be 10 °C. This study revealed the biology, in particular seed germination and emergence requirements, of the invasive weed T. portulacastrum that has spread in the Hula Valley in Israel and beyond. Future research will focus on an examination of control measures to combat this invasive weed.

Trianthema portulacastrum L. (Aizoaceae), commonly known as desert horse purslane or black pigweed, is a C4 dicot succulent invasive annual plant that is widespread in agricultural fields in Southeast Asia, tropical America, Africa, and Australia. In Israel, Trianthema portulacastrum is an invasive weed of increasing importance in agricultural fields, including mainly corn, tomato, alfalfa watermelon, and groundnut crops. The significance of this weed in crops has been recently reported in neighboring countries of Jordan and Egypt. In previous studies, we have examined and described the spread, biology, and germination requirements of Trianthema portulacastrum in Israel. The present study aimed to investigate the efficiency of single pre- and post-emergence herbicides and the combination of pre-applied herbicides for the control of this invasive weed in pots in a nethouse. We conducted three sequential experiments in a nethouse: (1) screening of pre-emergence herbicides, (2) screening of post-emergence herbicides, and (3) assessment of residual activity of combined pre-emergence herbicides in three distinct Hula Valley soil types. Efficacy was evaluated through weekly assessments of seedling emergence and vigor, with the final shoot fresh weight determined upon the experiment’s completion. In all experiments, weekly counts and vigor estimation of T. portulacastrum seedlings were conducted, and shoot fresh weights were determined at the end of the experiments. The results of pre-emergence herbicide screening showed that Fomesafen, Terbutryne, Flurochloridon, Sulfosulfuron, Cyrosulfamid + Izoxaflutole, and Dimethenamid were the most effective herbicides, leading to complete eradication of T. portulacastrum plants. Results of the post-emergence screening revealed that Saflufenacil, Foramsulfuron, Tembotrione + Isoxdifen-ethyl, and Rimsulfurom Methyl completely controlled the weed. In the soil residual study, three herbicide combinations (Fomesafen + Terbutryn, Sulfosulfuron + Fomesafen, and Dimethenamid + Flurochloridon) provided effective control across all soil types. These findings provide a foundation for future field trials investigating integrated pre- and post-emergence herbicide programs for T. portulacastrum management in various crops.