In recent years, phytoplasma diseases have increased and become serious in Egypt. Samples of carrot
plants exhibiting resemble symptoms of phytoplasma diseases were collected from seven different cultivated
areas in El Qalyubia governorate during the growing seasons 2021 and 2022; to detect phytoplasma infection
used Light microscopy, Dienes’ stain, transmission electron microscopy (TEM), and Nested-PCR. Dodder
(Cuscuta campestris), leafhopper (Hebata decipiens), and seed transmission were used to study the transability
of phytoplasma. The obtained results showed pleomorphic bodies in infected phloem tissues treated with
Dienes’ stain as irregular patches of intensely dark blue stained cells. However, a light microscope observed
significant abnormal changes in infected tissues compared with healthy ones. Transmission electron microscopy
(TEM) that observed phytoplasma units in the phloem tissue and deterioration in the ultrastructure of infected
plants including malformed cells, thickness, and abnormal shape of the cell wall. But, due to inconsistent
distribution within the plant, low titer, and fluctuation often hamper accurate phytoplasma detection. Therefore,
a PCR was used to detect phytoplasma infection using the universal primer pairs P1/P7 and R16F2n/R16R2 that
produce fragments at 1200 bp. For transmission of phytoplasma in carrot, dodder, and leafhoppers gave positive
results and mechanical transmission gave negative results. Our results will provide a better understanding of the
effects of phytoplasma infection in carrots, helping us to develop effective strategies for overcoming such
diseases.