BP Singh

Treatment Schedules for Eradication of Nematodes from Germplasm 221Contd ..... (Table 1)Plant9. Grapevine10. PomegranatematerialM. incognita andM. javanicaM. incognitaNematode Treatmeta) HWT of roots at 4snC for20 min. followed bytreatment at SO°C for 10min.a) HWT of roots at SO°C for10 min. followed bytreatment at S2°C for 10min.shoot remains and leaf fragments etc. attached to the stools - theheat does not have to penetrate to worms deep seated wi,thin planttissue. A perfect control could be achieved by treating stools at 46°C for 5 min with less damage to the plants than from the previouslyrecommended treatment of 43.3°C for 20-30 min. Although theshort treatment is usually safer and more convenient. Someworkers found that a few varieties were less harmed by the oldertreatment of 43.3°C for 20-30 min. and they found it possible toclassify chrysanthemum varieties according to their tolerance ofboth systems of treatmentFollowing success with 46°C treatment for chrysanthemums,scientists treated strawberry runners at that temperature for 7 min.and obtained good control of D. dipsaci without damage to the. plants. Slightly longer treatment appeared to be necessary to kill"Aphelenchoides spp. in strawberries, and for these it was suggested10 min. It was found that a more severe treatment 49°C for 20 min.was necessary to produce nematode free runners for. a strawberrycertification scheme, potted plants being treated upside down andonly the crown and leaves immersed.The nematodes M. incognita and Rotylenchulus reniformiswere completely eliminated from heavily infested sweet potatoplants by immersing the pl~nts in water at SO°C for 3-5 min. Insome cases immersion for longer periods up to 20 min. killed orseverely damaged plants (~artin, 1970).Hot water treatment of rhizomes of bananas to' controlburrowing nematode is improved by peeling all necrotic tissuefrom the corms before treatment. HWT of pared banana sets is