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AR TICLE the Inclusion of Downy Mildews in a Multi-Locus-Dataset

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GRLLPDIXQJXV IMA FUNGUS · VOLUME 2 · NO 2: 163–171 The inclusion of downy mildews in a multi-locus-dataset and its reanalysis ARTICLE reveals a high degree of paraphyly in Phytophthora )DELDQ5XQJH6DELQH7HOOH6HEDVWLDQ3ORFK(OL]DEHWK6DYRU\%UDG'D\5DKXO6KDUPDDQG0DUFR7KLQHV 8QLYHUVLW\RI+RKHQKHLP,QVWLWXWHRI%RWDQ\'6WXWWJDUW*HUPDQ\ %LRGLYHUVLW\DQG&OLPDWH5HVHDUFK&HQWUH %L.) 6HQFNHQEHUJDQODJH')UDQNIXUWDP0DLQ*HUPDQ\FRUUHVSRQGLQJDXWKRUHPDLO PDUFRWKLQHV#VHQFNHQEHUJGH 6HQFNHQEHUJ*HVHOOVFKDIWIU1DWXUIRUVFKXQJ6HQFNHQEHUJDQODJH')UDQNIXUWDP0DLQ*HUPDQ\ 0LFKLJDQ6WDWH8QLYHUVLW\'HSDUWPHQWRI3ODQW3DWKRORJ\&HQWHUIRU,QWHJUDWHG3ODQW6\VWHPV(DVW/DQVLQJ0,86$ *RHWKH 8QLYHUVLW\ )UDQNIXUW DP 0DLQ 'HSDUWPHQW RI %LRORJLFDO 6FLHQFHV ,QVWLWXWH RI (FRORJ\ (YROXWLRQ DQG 'LYHUVLW\ 6LHVPD\HUVWU ')UDQNIXUW 0DLQ *HUPDQ\ Abstract: 3DWKRJHQVEHORQJLQJWRWKHOomycota, a group of heterokont, fungal-like organisms, are amongst the Key words: PRVWQRWRULRXVSDWKRJHQVLQDJULFXOWXUH,QSDUWLFXODUWKHREOLJDWHELRWURSKLFGRZQ\PLOGHZVDQGWKHKHPLELRWURSKLF $8WHVW members of the genus Phytophthora are responsible for a huge variety of destructive diseases, including sudden downy mildews oak death caused by P. ramorum, potato late blight caused by P. infestans, cucurbit downy mildew caused by multigene phylogeny Pseudoperonospora cubensis, and grape downy mildew caused by Plasmopara viticola$ERXWVSHFLHVRI Peronosporaceae GRZQ\PLOGHZVDQGURXJKO\VSHFLHVRIPhytophthora are currently accepted, and recent studies have revealed Phytophthora WKDW WKHVH JURXSV DUH FORVHO\ UHODWHG +RZHYHU WKH GHJUHH WR ZKLFK Phytophthora is paraphyletic and where taxonomy exactly the downy mildews insert into this genus in relation to other clades could not be inferred with certainty to GDWH+HUHZHSUHVHQWDPROHFXODUSK\ORJHQ\HQFRPSDVVLQJDOOFODGHVRIPhytophthora as represented in a multi- ORFXVGDWDVHWDQGWZRUHSUHVHQWDWLYHVRIWKHPRQRSK\OHWLFGRZQ\PLOGHZVIURPGLYHUJHQWJHQHUD2XUUHVXOWV demonstrate that PhytophthoraLVDWOHDVWVL[WLPHVSDUDSK\OHWLFZLWKUHVSHFWWRWKHGRZQ\PLOGHZV7KHGRZQ\ PLOGHZUHSUHVHQWDWLYHVDUHFRQVLVWHQWO\QHVWHGZLWKLQFODGH FRQWDLQVPhytophthora palmivora ZKLFKLVSODFHG VLVWHUWRFODGH FRQWDLQVPhytophthora infestans 7KLV¿QGLQJZRXOGHLWKHUQHFHVVLWDWHSODFLQJDOOGRZQ\PLOGHZV and Phytopthora species in a single genus, either under the oldest generic name Peronospora or by conservation the later name Phytophthora, or the description of at least six new genera within Phytophthora7KHFRPSOLFDWLRQV of both options are discussed, and it is concluded that the latter is preferable, as it warrants fewer name changes DQGLVPRUHSUDFWLFDO Article info:6XEPLWWHG6HSWHPEHU$FFHSWHG2FWREHU3XEOLVKHG1RYHPEHU INTRODUCTION *|NHU et al 7KLQHV et al. 7KLQHV 7KH FORVH UHODWLRQVKLS RI WKH GRZQ\ PLOGHZV DQG 2RP\FHWHV DUH D JURXS RI RUJDQLVPV WKDW VXSHU¿FLDOO\ Phytophthora revealed by these studies is in contrast to the resemble fungi in their hyphal growth and absorptive way of ZLGHO\ XVHG WD[RQRPLF FODVVL¿FDWLRQV RI :DWHUKRXVH QXWULWLRQ +RZHYHU WKH\ DUH QRW FORVHO\ UHODWHG WR Mycota, DQG 'LFN LQ ZKLFK Phytophthora and Pythium but belong to a group of heterokont organisms, Straminipila were grouped together in the family Pythiaceae $OWKRXJK 'LFN ZKLFK DOVR LQFOXGHV GLDWRPV DQG VHDZHHGV &RRNHet al LQIHUUHGDSRVLWLRQRIPeronospora sparsa 2RP\FHWHVKDYHDGDSWHGWRSDUDVLWLVPRISODQWVDWOHDVWWKUHH DVDVLVWHUJURXSRIFODGH DVGH¿QHGLQWKDWVWXG\ EDVHGRQ times, once in the Saprolegniales in the genera Aphanomyces ,76VHTXHQFHVDORQHQRVXEVWDQWLDOSK\ORJHQHWLFUHVROXWLRQ and Pachymetra 5LHWKPOOHUet al.'LpJXH]8ULEHRQGR was present on the phylogenetic backbone, thus failing to et al DQGVHSDUDWHO\LQAlbuginales and Peronosporales position this group within the genus Phytophthora 2WKHU 5LHWKPOOHUet al. +XGVSHWKet al. 7KLQHVet al VWXGLHV LQFOXGLQJPXOWLORFXVVWXGLHV WKDWLQFOXGHGERWKGRZQ\ :KLOHWKHHYROXWLRQRIREOLJDWHELRWURSK\VHHPVWREH mildew and Phytophthora species have so far not resolved the DQ DQFLHQW RFFXUUHQFH IRU WKH ZKLWH EOLVWHU UXVWV 7KLQHV placement of downy mildews in relation to the different clades .DPRXQ WKHGRZQ\PLOGHZVKDYHPRUHUHFHQWO\DULVHQ of Phytophthora 5LHWKPOOHU et al *|NHU et al from PhytophthoraOLNH DQFHVWRUV 5LHWKPOOHU et al 7KLQHVet al.*LUHVVHet al. $GGLWLRQDOO\7KLQHVet © 2011 International Mycological Association You are free to share - to copy, distribute and transmit the work, under the following conditions: Attribution: <RXPXVWDWWULEXWHWKHZRUNLQWKHPDQQHUVSHFL¿HGE\WKHDXWKRURUOLFHQVRU EXWQRWLQDQ\ZD\WKDWVXJJHVWVWKDWWKH\HQGRUVH\RXRU\RXUXVHRIWKHZRUN Non-commercial: <RXPD\QRWXVHWKLVZRUNIRUFRPPHUFLDOSXUSRVHV No derivative works: <RXPD\QRWDOWHUWUDQVIRUPRUEXLOGXSRQWKLVZRUN For any reuse or distribution, you must make clear to others the license terms of this work, which can be found at http://creativecommons.org/licenses/by-nc-nd/3.0/legalcode. Any of the above conditions can be waived if you get permission from the copyright holder. Nothing in this license impairs or restricts the author’s moral rights. VOLUME 2 · NO. 2 163 Runge et al. al GHPRQVWUDWHGWKDWWKHVXSSRUWIRUWKHVLVWHUJURXS FRPSXWHUSDFNDJHY /DVHUJHQH0DGLVRQ:, DQGZHUH relationship of PeronosporaDQGFODGHLQIHUUHGE\&RRNHet DOLJQHGVHSDUDWHO\XVLQJ0$))7Y .DWRKet al al FRXOGKDYHEHHQWKHUHVXOWRIDQDOLJQPHQWDUWHIDFW XVLQJ D ZHEVHUYHU LQWHUIDFH KWWSZZZJHQRPHMSWRROV &RQYHUVHO\DUHFHQWVWXG\E\%ODLUet al DGGUHVVHGWKH PDIIW 7KH*,16LDOJRULWKPZDVFKRVHQIRUDOODOLJQPHQWV phylogenetic relationships of Phytophthora species with good 6XEVHTXHQWO\ WKH DOLJQHG VHTXHQFHV ZHUH FRQFDWHQDWHG ARTICLE resolution, but no downy mildew was included in that study, for phylogenetic analyses and no further editing was done OHDYLQJWKHLUSODFHPHQWWRVSHFXODWLRQ'RZQ\PLOGHZVKDYH on the alignment to ensure reproducibility and to prevent EHHQ VKRZQ WR EH D PRQRSK\OHWLF DVVHPEODJH E\ *|NHU et LQWURGXFWLRQRIELDV$IWHUWKHUHPRYDORIOHDGLQJDQGWUDLOLQJ al. +RZHYHU*|NHU 6WDPDWDNLV ODWHU LQVSLWH JDSVQXFOHRWLGHVLWHVZHUHLQFOXGHGLQWKHSK\ORJHQHWLF RIEHLQJSXEOLVKHGHDUOLHUWKDQ*|NHUet al. FDPHWRWKH DQDO\VHV7KHVHFRPSULVHGVHYHQORFLESRIWKHEHWD conclusion that a placement of PhytophthoraFODGHZLWKLQWKH WXEXOLQJHQHESRIWKH6ULERVRPDOSURWHLQ/JHQH downy mildews would also be possible, although no support ESRIWKHWUDQVODWLRQHORQJDWLRQIDFWRUDOSKDJHQH FRXOG EH REWDLQHG IRU WKLV VFHQDULR 7KH TXHVWLRQ RI ZKLFK ESRIWKH6QXFOHDU ULERVRPDO'1$JHQH ESRIWKH is the sister clade of the downy mildews, and how this clade JO\FHUDOGHK\GHSKRVSKDWHGHK\GURJHQDVHJHQHES is embedded among the different lineages of Phytophthora RIWKHKHDWVKRFNSURWHLQJHQHDQGESRIWKHHQRODVH therefore continues to be controversial, but is fundamental for JHQH7KHDOLJQPHQWWRJHWKHUZLWKWKHWUHHIURPWKH%D\HVLDQ understanding the evolution of this group of important plant $QDO\VLVVKRZQLQ)LJKDVEHHQGHSRVLWHGLQ7UHH%$6( SDWKRJHQVHVSHFLDOO\ZLWKUHVSHFWWRWKHHYROXWLRQRIELRWURSK\ ZZZWUHHEDVHRUJ XQGHUWKHDFFHVVLRQQXPEHU6 In addition, the taxonomic status of many Phytophthora 7KHJHQHUDOWLPHUHYHUVLEOH *75 PRGHOZDVVHOHFWHGIRU VSHFLHVGHSHQGVRQWKHGHJUHHRISDUDSK\O\RIWKHJHQXV$W WKHFRQFDWHQDWHGDOLJQPHQWXVLQJ0RGHOWHVWY 3RVDGD OHDVWZLWKWZRFODGHVDQGPhytophthora is paraphyletic &UDQGDOO DQG3$83YE 6ZRIIRUG ZLWK ZLWKUHVSHFWWRGRZQ\PLOGHZV &RRNHet al*|NHUet al. JDPPDGLVWULEXWHG VXEVWLWXWLRQ UDWHV VKDSH SDUDPHWHU 7KLQHVet al EXWVRIDUWKHGHJUHHRISDUDSK\O\ DQG SURSRUWLRQ RI LQYDULDEOH VLWHV SLQY 7KH of Phytophthora FRXOG QRW EH UHVROYHG 7KHUHIRUH LW ZDV YDOXHV RI WKHVH SDUDPHWHUV ZHUH LQFOXGHG LQ WKH %D\HVLDQ the aim of this study to resolve the phylogenetic placement DQG0LQLPXP(YROXWLRQDQDO\VHV RIWKHPRQRSK\OHWLFGRZQ\PLOGHZV UHSUHVHQWHGE\WKHWZR 0LQLPXP(YROXWLRQ 0( DQDO\VLVZDVGRQHXVLQJ0(*$ divergent downy mildew genera for which genome data are Y 7DPXUD et al. ZLWK WKH JDPPDGLVWULEXWHG FXUUHQWO\ DYDLODEOH DPRQJ Phytophthora and to test this VXEVWLWXWLRQ UDWHV DV LQIHUUHG E\ 0RGHOWHVW DQG XVLQJ placement statistically, to further clarify the relationships within WKH 0D[LPXP&RPSRVLWH/LNHOLKRRG VXEVWLWXWLRQ PRGHO WKLVJURXSRILPSRUWDQWSODQWSDWKRJHQV )RU LQIHUULQJ WUHH UREXVWQHVV ERRWVWUDS UHSOLFDWHV )HOVHQVWHLQ ZHUHFRPSXWHG )RU 0D[LPXP /LNHOLKRRG 0/ LQIHUHQFH WKH 5$[0/ MATERIALS AND METHODS ZHEVHUYHU DW KWWSSK\OREHQFKYLWDOLWFKUD[POEE 6WDPDWDNLV et al ZDV XVHG ZLWK VWDQGDUG VHWWLQJV $OOVHTXHQFHVRIPhytophthora and Pythium were obtained and maximum likelihood search, including an estimation of IURPWKHVWXG\RI%ODLUet al DYDLODEOHLQWKH1DWLRQDO LQYDULDEOH VLWHV7KH DQDO\VLV ZDV UHSHDWHG ¿YH WLPHV ZLWK &HQWHU IRU %LRWHFKQRORJ\ ,QIRUPDWLRQ 1&%, QXFOHRWLGH ERRWVWUDSUHSOLFDWHVHDFK7KHERRWVWUDSVXSSRUWYDOXHV GDWDEDVH *HQ%DQN 7KH GDWDVHW LQFOXGHV VHTXHQFHV RI obtained were averaged, because the rapid bootstrapping seven different loci, and all species for which all seven loci DOJRULWKPFDQOHDGWRVRPHGHYLDWLRQ were not available were discarded, except for two Pythium )RU%D\HVLDQDQDO\VLV0U%D\HV +XHOVHQEHFN 5RQTXLVW VSHFLHVIRUZKLFKRQO\VL[RIWKHVHYHQORFLFRXOGEHREWDLQHG DWWKH3K\OHPRQZHEVHUYHU KWWSSK\OHPRQELRLQIR 7KLVUHVXOWHGLQDQRYHUDOOGDWDVHWRIVSHFLHVVDPSOHG FLSIHV DQG DW D ORFDO VHUYHU IRU SDUDOOHO UXQV ZDV XVHG 7KHVHTXHQFHVRIPhytophthora infestans were used to obtain )RXU LQFUHPHQWDOO\ KHDWHG VLPXOWDQHRXV 0DUNRY &KDLQ homologous sequences from the genome of Hyaloperonspora 0RQWH&DUORFKDLQVZHUHUXQIRUWZRPLOOLRQJHQHUDWLRQVZLWK arabidopsidisIURPWKH1&%,GDWDEDVHXVLQJ%/$67 $OWVFKXO HYHU\th tree sampled, under the general time reversible et al DQG IURP WKH JHQRPH RI Pseudoperonospora *75 PRGHO ZLWK WKH JDPPDGLVWULEXWHG VXEVWLWXWLRQ UDWHV cubensis 7LDQ et al XVLQJ WKH DQQRWDWHG (67 DQG SURSRUWLRQ RI LQYDULDEOH VLWHV DV LQIHUUHG E\ 0RGHOWHVW VHTXHQFHLQIRUPDWLRQ%HFDXVHQRVHTXHQFHLQIRUPDWLRQIRU
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  • Impact of Environmental Factors, Chemical Fungicide and Biological Control on Cacao Pod Production Dynamics and Black Pod Disease (Phytophthora Megakarya) in Cameroon

    Impact of Environmental Factors, Chemical Fungicide and Biological Control on Cacao Pod Production Dynamics and Black Pod Disease (Phytophthora Megakarya) in Cameroon

    Available online at www.sciencedirect.com Biological Control 44 (2008) 149–159 www.elsevier.com/locate/ybcon Impact of environmental factors, chemical fungicide and biological control on cacao pod production dynamics and black pod disease (Phytophthora megakarya) in Cameroon P. Deberdt a,b,*, C.V. Mfegue c, P.R. Tondje c, M.C. Bon d, M. Ducamp e, C. Hurard d, B.A.D. Begoude c, M. Ndoumbe-Nkeng c, P.K. Hebbar f, C. Cilas g a CIRAD, UPR Bioagresseurs de Pe´rennes, Saint Augustine, Trinidad and Tobago b CIRAD, UPR Bioagresseurs de Pe´rennes, Montpellier, F-34398, France c IRAD, Regional Biological Control and Applied Microbiology Laboratory, P.O. Box 2067, Yaounde´, Cameroon d USDA-ARS-EBCL, Campus International de Baillarguet, 34980 Montferrier le Lez, France e CIRAD, UMR BGPI, TAA-54K, Campus International de Baillarguet, Montpellier F-34398, France f MARS Inc./USDA-ARS, Sustainable Perennial Crops Laboratory, Beltsville, MD 20705, USA g CIRAD, UPR Bioagresseurs de Pe´rennes, Montpellier F-34398, France Received 14 February 2007; accepted 30 October 2007 Available online 5 November 2007 Abstract The impact of environmental factors and microbial and chemical control methods on cacao pod production dynamics and spread of black pod disease caused by Phytophthora megakarya was assessed over three consecutive years in a smallholder’s plantation. Significant positive correlations were found between rainfall records and pod rot incidence when assessed after a 1-week lag. Disease distribution across various pod developmental stages showed that immature pods were the most susceptible to P. megakarya attack. Weekly obser- vations of the pod distribution and disease progression at various developmental stages on cacao trees sprayed with fungicide Ridomil, Trichoderma asperellum biocontrol agent (strain PR11), or untreated control trees indicated that the total pod production and the inci- dence of black pod rot was significantly different between the treatments.
  • Predicting Lifestyle and Host from Positive Selection Data and Genome Properties in Oomycetes

    Predicting Lifestyle and Host from Positive Selection Data and Genome Properties in Oomycetes

    bioRxiv preprint doi: https://doi.org/10.1101/2021.01.12.426341; this version posted March 25, 2021. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC 4.0 International license. G´omez-P´erez and Kemen RESEARCH Predicting lifestyle and host from positive selection data and genome properties in oomycetes Daniel Gomez-P´ ´erez* and Eric Kemen *Correspondence: daniel.gomez- [email protected] Abstract Zentrum fur¨ Molekularbiologie der Pflanzen, Auf der Morgenstelle 32, Background: Host and niche shifts are a source of genomic and phenotypic 72076 Tubingen,¨ Germany diversification as evidenced in parasitism. Exemplary is core metabolism reduction Full list of author information is as parasites adapt to a particular host, while the accessory genome often available at the end of the article maintains a high degree of diversification. However, selective pressures acting on the genome of organisms that have undergone lifestyle or host change have not been fully investigated. Results: Here, we developed a comparative genomics approach to study underlying adaptive trends in oomycetes, a eukaryotic phylum with a broad range of economically important plant and animal parasitic lifestyles. Our analysis reveals converging evolution on biological processes for oomycetes that have similar lifestyle. Besides, we find that certain functions, in particular carbohydrate metabolism, transport, and signaling, are important for host and environmental adaption in oomycetes. Discussion: Given the high correlation between lifestyle and genome properties in our oomycete dataset and the convergent evolution of fungal and oomycete genomes, we have developed a model that predicts plant pathogen lifestyles with high accuracy based on functional annotations.
  • The Phytophthora Cactorum Genome Provides Insights Into The

    The Phytophthora Cactorum Genome Provides Insights Into The

    www.nature.com/scientificreports Corrected: Author Correction OPEN The Phytophthora cactorum genome provides insights into the adaptation to host defense Received: 30 October 2017 Accepted: 12 April 2018 compounds and fungicides Published online: 25 April 2018 Min Yang1,2, Shengchang Duan1,3, Xinyue Mei1,2, Huichuan Huang 1,2, Wei Chen1,4, Yixiang Liu1,2, Cunwu Guo1,2, Ting Yang1,2, Wei Wei1,2, Xili Liu5, Xiahong He1,2, Yang Dong1,4 & Shusheng Zhu1,2 Phytophthora cactorum is a homothallic oomycete pathogen, which has a wide host range and high capability to adapt to host defense compounds and fungicides. Here we report the 121.5 Mb genome assembly of the P. cactorum using the third-generation single-molecule real-time (SMRT) sequencing technology. It is the second largest genome sequenced so far in the Phytophthora genera, which contains 27,981 protein-coding genes. Comparison with other Phytophthora genomes showed that P. cactorum had a closer relationship with P. parasitica, P. infestans and P. capsici. P. cactorum has similar gene families in the secondary metabolism and pathogenicity-related efector proteins compared with other oomycete species, but specifc gene families associated with detoxifcation enzymes and carbohydrate-active enzymes (CAZymes) underwent expansion in P. cactorum. P. cactorum had a higher utilization and detoxifcation ability against ginsenosides–a group of defense compounds from Panax notoginseng–compared with the narrow host pathogen P. sojae. The elevated expression levels of detoxifcation enzymes and hydrolase activity-associated genes after exposure to ginsenosides further supported that the high detoxifcation and utilization ability of P. cactorum play a crucial role in the rapid adaptability of the pathogen to host plant defense compounds and fungicides.
  • Testing for the Resistance of Newly Generated Hybrid Cacao Germplasm

    Testing for the Resistance of Newly Generated Hybrid Cacao Germplasm

    bioRxiv preprint doi: https://doi.org/10.1101/2020.12.07.414466; this version posted December 7, 2020. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY 4.0 International license. 1 Testing for the resistance of newly generated hybrid cacao 2 germplasm in the gene pool of Cocoa Research Institute of 3 Nigeria (CRIN) against Phytophthora megakarya pathogen 4 causing black pod disease of cocoa 5 6 Tijani, A. A.23*¶, Otuonye, A. H.1¶, Otusanya, M. O.3&, Olaiya, A. O.4&, Adenuga, O. 7 O.2& and Afolabi, C. G.3¶ 8 9 1. Department of Plant Protection, Cocoa Research Institute of Nigeria, Ibadan, Nigeria 10 2. Department of Plant Improvement, Cocoa Research Institute of Nigeria, Ibadan, Nigeria 11 3. Department of Plant Protection, Federal University of Agriculture Abeokuta, Abeokuta, 12 Nigeria 13 4. Department of Crop Physiology, Federal University of Agriculture Abeokuta, Abeokuta, 14 Nigeria 15 ¶ These authors contributed equally to this work. 16 & These authors also contributed equally to this work. 17 *Corresponding author: E-mail Address: [email protected] (A. A.): Contact address: CRIN, 18 PMB 5244, Idi-Ayunre, Ibadan. 19 20 ABSTRACT 21 bioRxiv preprint doi: https://doi.org/10.1101/2020.12.07.414466; this version posted December 7, 2020. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity.
  • Mildew (Peronospora Sparsa)

    Mildew (Peronospora Sparsa)

    A review into control measures for blackberry downy mildew (Peronospora sparsa) Guy Johnson and Ruth D’Urban-Jackson ADAS Boxworth, Battlegate Road, Cambridgeshire, CB23 4NN Background Control of downy mildew in commercial blackberry production is becoming increasingly difficult. Losses of effective spray control products in recent years, particularly close to harvest, have exacerbated the problem. Novel and alternative approaches will be required in future. AHDB has already funded several projects to assess new control measures, but this desk study aims to identify additional ideas. Summary of main findings • Use of protected cropping to reduce leaf wetness will help minimise infection • Good site selection to maximise light interception, maintain good air movement and avoid natural sources of infection is important • Maintain good air movement by removing weed growth in the crop vicinity and managing the crop to avoid excessive vegetative growth • Reduce relative humidity below 85%. The use of air fans in glasshouse crops improves air movement • Manage nitrogen application carefully to avoid excessive leaf growth • Photoselective polythene to alter the wavelength of light reaching the crop could affect the infection rate, but this requires further study • The efficacy of the currently approved biopesticide control agents Serenade ASO, Sonata, Amylo X and Prestop requires further assessment • Elicitors (such as potassium phosphite) and plant extracts are known to offer varying levels of control, but these need further screening to assess