Mango grafting failure disease: associated fungi and possible control

Grafting failure (GF) disease is the main problem facing mango seedlings production in nurseries located at three governorates during 2019 and 2020 seasons. The highest percentage (GF) was recorded at El Manashy nursery, Giza governorate, followed by El Qanater nursery, Qalyoubiya governorate, while the lowest% disease incidence was observed at Ismailia nursery, Ismailia governorate. The highest values of (GF) disease incidence on permutations and combinations of rootstock/scion in the three nurseries during the two years were recorded on Zebda/Kiett, Zebda/Sedeek and Balady/Kiett, followed by Balady/Sedeek, Sokkary/Kiett and Zebda/Ewais. On the other hand, the lowest susceptible rootstock/scion combinations were Sokkary/Sedeek, Balady/Ewais and Sokkary/Ewais. Lasiodiplodia theobromae was the most frequently isolated fungus and the most pathogenic on all permutations and combinations of rootstock/scion, followed by Fusarium solani. During grafting under greenhouse conditions, dipping Kiett, Ewais and Sedeek scions in the suspension of each of the tested commercial products before dipping in spore suspension of each pathogenic fungus, L. theobromae and F. solani reduced the percentage of (GF) of all permutations and combinations of rootstock/scion compared to the untreated scions. Also during grafting under nursery conditions, dipping mango scions in each of the tested treatments increased the % grafting success of all permutations and combinations of rootstock/scion compared to the untreated scions. In this respect, Copper oxide nanoparticles and Kemazed were the most effective which recorded (96.1 and 97.2) and (92.7 and 96.1) % success of mango grafted seedlings during the two seasons, respectively, followed by Biocontrol T34, Serenade ASO and Lemongrass oil being (87.2 and 90.5), (85.5 and 88.3) and (83.3 and 87.2), respectively. While the lowest % success was recorded when scions were dipped in Hydrogen Peroxide and Jojoba oil being (81.1 and 86.6) and (80.0 and 84.4), respectively. It is concluded that improving mango seedlings production in nurseries can be achieved by producing compatible rootstock-scion through controlling (GF) disease by using alternative and eco-friendly products beside to chemical products to obtain much higher economic returns with the least possible damage to the environment.