DI (A) and CE (B) of Chitosan, Lentinan and Ningnanmycin on PRSV in papaya in fruiting stage. Whereas CK—control without the use of bio-pesticides, C—use of 0.50 g L−1 Chitosan, L—use of 10.00 g L−1 Lentinan, N—use of 0.05 g L−1 Ningnanmycin, CL—Chitosan plus Lentinan, CN—Chitosan plus Ningnanmycin, LN—Lentinan plus Ningnanmycin, CLN—Chitosan plus Lentinan plus Ningnanmycin. Each papaya plant was irrigated with 5 L and sprayed with 6 L biological pesticide once every 7 to 14 days. NT—negative control without PRSV inoculation. Different lowercase letters indicate significant differences at the 0.05 level.