In two SCEPTREplus trial across plum and ornamental plants this year , a range of works shelter products ( PPPs ) will be sort for efficacy against rust fungus . Some active purpose to preclude rust spores from germinating , whilst others spark the plant life ’s defences , priming it for an attack .
decorative plantsAlthough there is a reach of important rusting pathogens , the tribulation will focus on heuchera as a role model ornamental crop .
genus Heuchera rust ( P. genus Heuchera ) is far-flung in both the USA and East Asia . It was first reported in the UK in 2004 , then at many commercial greenhouse the following yr . Within commercial-grade production , if plants do not invite suitable fungicide applications , pustules form on leaves and can result in unmarketable plants . new pustules incline to erupt on both young and erstwhile leaves from March to May , and then again from August to November .
Figure 1 . Heuchera rust fungus pustules construe on the undersurface of Heuchera ‘ Sloeberry ’ in April . Cambridgeshire , UK .
former AHDB - funded inquiry suggest that any heuchera variety show can succumb to rust fungus , but certain variety such as ‘ Palace Purple ’ , ‘ Plum Pudding ’ and ‘ Fire Chief ’ appeared to be less prone . Whilst tolerant cultivar and good hygiene on site can minimise losings to heuchera rust fungus , agriculturalist are still heavy dependant on the strobilurin group of fungicides , and would benefit in induce admittance to second - generation succinate dehydrogenase inhibitor ( SDHIs ) , to create a good electric resistance direction programme in line with fungicide resistance action committee ( FRAC ) .
The trial is being set up at ADAS Boxworth on Heuchera ‘ Key Lime Pie ’ , where screen out of promising products will commence this August .
PlumIn an industry deserving £ 8.6 million , plum rust fungus ( Tranzschelia discolor ) is a major trouble in the UK , hitting cultivars such as Victoria particularly badly . Consumer requirement for know varieties often fix widespread adoption of resistant cultivars . Where status for rust pass off early in the season , the disease rigourousness can overwhelm Tree and premature defoliation can impact concede both in that time of year but also the following yr , as the tree diagram does n’t build up up the resources it would have ordinarily . Since the exit of Systhane ( myclobutanil ) in 2018 , plum growers have not had access to any rusting - specific plant tribute products .
Figure 2 . A , septic plum leaves with rust pustules on leaf underside ( provide ) and chicken speckling on upper leaf surface ( right ) . B , freshly emerging plum leaves in May 2019 . atomic number 6 , test set - up in Ely , Cambridgeshire .
Work is underway in setting up our trial , tree have been planted ( Figure 2 , B and C ) , and the intersection masking will begin in belatedly this summertime when rusting disease pressure level is high .
For more information : AHDBhorticulture.ahdb.org.uk/
