Effects of cranberry juice and pineapple juice on Pratylenchus coffeae.

Abstract

The nematodes killed by cranberry juice often had puffed cuticle similar to the blisters on human skin after been scalded by boiling water. There were 75.7% coffeae with puffed cuticles after 96 h exposure to cranberry juice. None of the nematodes in the fructose or pineapple juice treatment had puffed cuticle. Cranberry juice was very effective in killing all the developmental stages of P. coffeae. The mortality rates were 100% for J2 and male, 97% for female and 99% for J3+J4 after 96 h exposure. Dilution of cranberry juice to 1:5 rendered it ineffective in killing P. coffeae but 71.5% of nematodes were paralyzed after 96 h exposure. Cranberry juice remained very effective in killing P. coffeae after boiling for 2 minutes. The canned pineapple juice was completely ineffective in killing P. coffeae. However, hand-squeezed fresh pineapple juice caused high mortality of the nematodes. Boiling for 2 min rendered it completely ineffective. The cranberry juice and pineapple juice have different nematicidal principles as indicated by heat stability test and the difference in their ability to cause puffed cuticle. The infection of mung bean roots by P. coffeae was significantly reduced by cranberry juice and fresh pineapple juice in the growth chamber tests.