Phytomyza orobanchia Kalt.as a biological control agent of Orobanche crenata Forsk, in Alexansria, Egypt

Background The parasitic weed, Orobanche crenata Forsk (Orobanchaceae) is a noxious root parasite which seriously damage the production of many crops, particularly in the Leguminosae such as faba bean Vicia faba . Significant yield losses in faba bean fields can be attributed to its parasitism. Results The occurrence of Phtomyza orobanchia Kalt fly in faba bean fields naturally infested by the parasitic weed Orobanche crenata Forsk, was studied in two locations namely Abies and Nubaria farms during three successive faba bean seasons, 2020–2023 during, February, March and April (cool to warm temperature). The fly population was generally low in the 3 seasons in February, but increase to its maximum in late March in the 1st season and April in the 2nd and 3rd seasons. In Nubaria farm most larvae and puparia of Ph.orobanchia fly were found in fruits capsules with significantly lower proportions in plant base and stem parts. The fly preferred to attack the middle and upper fruits than lower ones. In Abies farm most of Ph. orobanchia flies were significantly found in plant base followed by plant capsules and the lowest proportion was in the plant stem. The Broomrapes are very prolific, producing thousands of tiny ripe Seeds/ plant. Thirty flowering Broomrape shoots produce 1,320 seed capsules. In one capsule, 4721.49 ripe seeds had been counted and an average of 207,247minute seeds can be produced per plant. Conclusions Infestation with Phytomyza fly is efficient in reducing Orobanche seed yield so has a great effect in the reduction of Orobanche seed bank. The work suggested that Ph. orobanchia could be a promising biological control agent of Orobanche spp. in Egypt, especially if resistance faba bean cultivar was grown and repeated field mass release techniques could be adopted.