Thermal Time Model for Egyptian Broomrape (Phelipanche aegyptiaca) Parasitism Dynamics in Carrot (Daucus carota L.): Field Validation

Abstract

Carrot, a highly profitable crop in Israel, is severely damaged by Phelipanche aegyptiaca parasitism. Herbicides can effectively control the parasite and prevent damage, but for optimal results, knowledge about the soil–subsurface phenological stage of the parasite is essential. Parasitism dynamics models have been successfully developed for the parasites P. aegyptiaca, Orobanche cumana, and Orobanche minor in the summer crops, tomato, sunflower, and red clover, respectively. However, these models, which are based on a linear relationship between thermal time and the parasitism dynamics, may not necessarily be directly applicable to the P. aegyptiaca–carrot system. The objective of the current study was to develop a thermal time model to predict the effect of P. aegyptiaca parasitism dynamics on carrot growth. For development and validation of the models, data was collected from a temperature-controlled growth experiment and from 13 plots naturally infested with P. aegyptiaca in commercial carrot fields. Our results revealed that P. aegyptiaca development is related to soil temperature. Moreover, unlike P. aegyptiaca parasitism in sunflower and tomato, which could be predicted both a linear model, P. aegyptiaca parasitism dynamics on carrot roots required a nonlinear model, due to the wider range of growth temperatures of both the carrot and the parasite. Hence, two different nonlinear models were developed for optimizing the prediction of P. aegyptiaca parasitism dynamics. Both models, a beta function model and combined model composed of a beta function and a sigmoid curve, were able to predict first P. aegyptiaca attachment. However, overall P. aegyptiaca dynamics was described more accurately by the combined model (RMSE = 14.58 and 10.79, respectively). The results of this study will complement previous studies on P. aegyptiaca management by herbicides to facilitate optimal carrot growth and handling in fields infested with P. aegyptiaca.

Recent research progress in combatting root parasitic weeds

“…In a decision support system developed in Israel for the control of P. aegyptiaca in tomato fields, the timing of the herbicide application was based on a thermal time model that was developed to predict parasitism of P. aegyptiaca on tomatoes [199]. The model was also effective for predicting the entire parasitism dynamics, not only for predicting the first attachment, and could be used for precise temporal chemical management of P. aegyptiaca in carrot (Daucus carota) fields [200]. Three sequential foliar applications of glyphosate at 108 g/ha completely controlled P. aegyptiaca in carrot fields [201,202].…”

An endophytic bacteria (Pseudomonas aeruginosa) strain translocated and protected tomato (Solanum lycopersicum L.) plants from its parasitic weed Phelipanche aegyptiaca

“…Starters were grown to turbidity OD=0.1 (600nm); then, the starters were used to inoculate the necessary volume of broth culture at a ratio of 1:100 (V:V) in an Erlenmeyer flask. 4…”

“…A wide variety of parasitic weed control methods have been applied in an attempt to control broomrape (Joel et al, 2006;Aly et al, 2009;Aly, 2007;Cochavi et al, 2016), most of which are based on chemical sprays that can be windborne and are toxic to non-target plants (Aly, 2007). Therefore, there is a need to find alternative solutions to reduce plant-plant parasitization.…”

Host-Parasite-Bacteria Triangle: The Microbiome of the Parasitic Weed Phelipanche aegyptiaca and Tomato-Solanum lycopersicum (Mill.) as a Host

“…A wide variety of parasitic weed control methods have been applied in attempts to control broomrape (Joel et al, 2006; Aly, 2007; Aly et al, 2009; Cochavi et al, 2016), most of which are based on chemical sprays that can be windborne and toxic to non-target plants. Therefore there is a need to find alternative solutions to reduce plant–plant parasitization.…”