▁ ▁F ict ional ▁al umn i ▁ ▁Mart y ▁By r de , ▁main ▁character ▁in ▁O z ark ▁played ▁by ▁Jason ▁Bat eman ▁ ▁References ▁ ▁* ▁Indiana ▁State ▁people ▁Indiana ▁State <0x0A> </s> ▁Pow der y ▁mil de w ▁is ▁a ▁fung al ▁disease ▁that ▁affect s ▁a ▁wide ▁range ▁of ▁plants . ▁Pow der y ▁mil de w ▁dise ases ▁are ▁caused ▁by ▁many ▁different ▁species ▁of ▁fung i ▁in ▁the ▁order ▁E ry si ph ales , ▁with ▁Pod os pha era ▁x anth ii ▁( a . k . a . ▁S pha er othe ca ▁ful ig inea ) ▁being ▁the ▁most ▁commonly ▁reported ▁cause . ▁ ▁E rys ip he ▁c ich or ace ar um ▁was ▁formerly ▁reported ▁to ▁be ▁the ▁primary ▁caus al ▁organ ism ▁throughout ▁most ▁of ▁the ▁world . ▁ ▁Pow der y ▁mil de w ▁is ▁one ▁of ▁the ▁easier ▁plant ▁dise ases ▁to ▁identify , ▁as ▁its ▁sympt oms ▁are ▁quite ▁distinct ive . ▁In fect ed ▁plants ▁display ▁white ▁pow der y ▁sp ots ▁on ▁the ▁leaves ▁and ▁st ems . ▁The ▁lower ▁leaves ▁are ▁the ▁most ▁affected , ▁but ▁the ▁mil de w ▁can ▁appear ▁on ▁any ▁above - ground ▁part ▁of ▁the ▁plant . ▁As ▁the ▁disease ▁progress es , ▁the ▁sp ots ▁get ▁larger ▁and ▁dens er ▁as ▁large ▁numbers ▁of ▁a sex ual ▁sp ores ▁are ▁formed , ▁and ▁the ▁mil de w ▁may ▁spread ▁up ▁and ▁down ▁the ▁length ▁of ▁the ▁plant .