zu ▁( P uer aria ▁phase olo ide ) ▁inter cro pped ▁with ▁y am ▁have ▁shown ▁to ▁potential ▁to ▁reduce ▁S . ▁br ad ys ▁population . ▁Similarly , ▁the ▁ex clusion ▁of ▁we ed ▁hosts ▁such ▁as ▁E up ator ium , ▁Syn ed rel la ▁and ▁Ch rom ola ena , ▁will ▁help ▁to ▁reduce ▁n emat ode ▁damage . ▁ ▁The ▁use ▁of ▁n emat ode - free ▁propag ative ▁material ▁is ▁the ▁most ▁appropriate ▁method ▁to ▁prevent ▁n emat ode ▁damage . ▁Se ed ▁tub ers ▁should ▁be ▁exam ined ▁before ▁plant ing ▁and ▁the ▁ones ▁showing ▁sympt oms ▁of ▁dry ▁rot ▁should ▁not ▁be ▁used . ▁It ▁is ▁important ▁to ▁note ▁that ▁in ▁tub es ▁not ▁showing ▁obvious ▁external ▁sympt oms ▁of ▁damage , ▁it ▁is ▁necessary ▁to ▁scra pe ▁away ▁the ▁surface ▁layers ▁to ▁determine ▁the ▁presence ▁of ▁dry ▁rot . ▁ ▁Hot ▁water ▁treatment ▁ ▁Studies ▁have ▁shown ▁that ▁tre ating ▁tub ers ▁with ▁hot ▁water ▁( 5 0 - 5 5   ° C ) ▁for ▁up ▁to ▁ 4 0 ▁min ▁gives ▁the ▁best ▁control ▁of ▁S . ▁br ad ys , ▁without ▁dam aging ▁the ▁tub ers . ▁However , ▁this ▁method ▁it ▁is ▁not ▁broad ly ▁used ▁because ▁of ▁the ▁cost , ▁labor ▁and ▁difficulties ▁of ▁maintain ing ▁constant ▁temper atures . ▁ ▁Res istance ▁and ▁toler ance ▁ ▁Full ▁resistance ▁to ▁S . ▁br ad ys ▁has ▁not ▁been ▁found ▁in ▁land ra ces ▁or ▁access ions ▁exam ined ▁in