1、Reading: Dreistadt et al 2004 - p. 21-48, 212-222; 349-472 Agrios Chapter 9 PNW Plant Disease Management Handbook,Lecture 19 PRINCIPLES OF DISEASE MANAGEMENT,Disease management (control) From PNW Plant Disease Management Handbook,Exclusion quarantines, inspections, certification Avoidance not planti
2、ng in poorly drained soils (Phytophthora), avoiding wounding Eradication crop rotation, sanitation, eliminating alternate hosts, fumigation Protection treating healthy plants before infection - fungicides Resistance genetic resistance tolerance, immunity,PRINCIPLES OF DISEASE MANAGEMENTCULTURALCHEMI
3、CALGENETIC - BREEDING FOR RESISTANCE/ BIOTECHNOLOGYBIOLOGICAL CONTROLQUARANTINEDOING NOTHING,1. CULTURAL Practices for producing healthy plants Improved growing conditions fertilization, soil organic matter, good drainage, avoid compaction Host removal Inoculum reduction removal of stumps and roots
4、for root diseases, raking and removal of infected leaves Pruning, thinning Crop rotation Sanitation debarking for Dutch elm disease, leaf raking Use of alternative species red cedar for laminated root rot Mulches - polyethylene tarps, bark, wood chips Suppressive soils/antagonism of other microbes A
5、ntagonistic plants - mustard Physical methods heat (black or clear plastic, steam), light, refrigeration,Verticillium wilt Japanese maple,Rose Powdery Mildew and Common Cultural Methods for Control,Powdery Mildew (Sphaerotheca pannosa)Overwinters in infected buds, canes and fallen leaves and attacks
6、 young spring growth. Thrives in areas with high relative humidity at night when temperatures are around 60 degrees F. Also thrives at around 80 degrees F with 40%-70% RH.,Best way to prevent powdery mildew and other diseases w/o using chemicals!Clean up fallen leaves, deadheads and other debris. DO
7、 NOT COMPOST!Allow adequate space for plants when planting to ensure good air circulation.Avoid overwatering, overhead watering, and applying too much fertilizer.Plant “resistant” varieties,2. CHEMICAL METHODSFungicidesFumigants methyl bromide, chloropicrin(still looking for alternative to MB)Contro
8、l of insect vectors e.g., Dutch elm disease,Fungicide application to control ergot on rye,Ethanedinitrile MB alternative,Agriculture fumigation,Forest nursery fumigation,Fumigant applicationmethods,FUNGICIDESClassified by chemical class or mode of action or by properties once in the plant.a. Chemica
9、l class organic or inorganic - best to mix or rotate materials found in different fungicide families.,b. Mode of action and properties in the plant (terms)Antibiotics - Streptomycin against fire blight Biofungicides Trichoderma harzianum, Pseudomonas syringae, Bacillus subtilis, Verticillium dahliae
10、 Broad spectrum - captan, sulfur Narrow spectrum - metalaxyl against Phytophthora Broad to narrow spectrum,Bactericidal Curative - generally act within the plant and are effective shortly after penetration Demethylation-inhibiting - funginex Eradicant (contact killing, prevent sporulation) Fungicida
11、l - kills fungi - Captan Fungistatic - inhibit fungi (metalaxyl) Fumigant - vapor action (methyl bromide),Nematicide Protectants - prevent spores from germinating - Bravo Systemic - usually absorbed by roots and translocated through plant (metalaxyl) some move downward (Aliette - stimulates host def
12、ense mechanisms) Locally systemic - dont move far in the plant Thiophanate methyl Vapor action - fumigants,c. Common fungicides in the home landscape (multiple modes of action)Captan - broad spectrum - leaf spots, blights (not good against powedery mildews and rust)Chlorothaninol (Daconil 2878, Fung
13、-onil, Bravo) - broad spectrum. Foliar treatmentCopper based compounds (Bordeaux mix , copper sulfate) downy mildew on grapes, many fungal and bacterial leaf diseases and cankersHorticultural and botanical oils (Neem oil, pesticidal oil) good eradicants powdery mildew,Lime sulfur or calcium polysulf
14、ide (Lime sulfur) - eradicant and dormant spray - powdery mildew, scab, brown rot, leaf curls, rusts and mites - can burnMancozeb (Greenlight broad spectrum) fungal diseases - lawns, fruits, vegetables, ornamentalsMycobutanil (Immunox, Spectricide) powdery mildews,rusts, leaf spotsPCNB (pentachloron
15、itrobenzene) - soil fungicide lawn snow mouldSoaps (Safers Insecticidal Soap) powdery mildews Sodium or Potassium bicarbonates not very effective,Streptomycin (Fire Blight Spray)Sulfur (Safers Garden Fungicide) - elemental sulphur - powdery mildew and leaf blights - can burn Thiophanate methyl (Gree
16、n Light Systemic Fungicide) - ornamentals, lawns, some fruit treesTriforine (Funginex) - locally systemic - powdery mildews, leaf spots, blights Compost tea foliage diseases. Does it work?Fungicides may also need spray adjuvant to work - stickers, etc.,Rhododendron - Phytophthora root disease How to
17、 treat?,3. BREEDING FOR RESISTANCE/ BIOTECHNOLOGYResistant species and varieties, molecular techniques - gene transfer,Resistant cherry in Arboretum?,4. BIOLOGICAL CONTROLWith antagonistic fungi and bacteria, mycorrhizae, antibiotics Fungi Trichoderma harzianum, Verticillium dahliaeBacteriaPseudomon
18、as syringae, Bacillus subtilis,BIOLOGICAL CONTROLMYCORRHIZAE Mycorrhizae (fine root/fungal muutalistic symbiotic association) - Fungus protects plants against pathogens Mix of ectomycorrhizae and arbuscular mycorrhizae,Phytophthora lateralis in the Arboretum Success story for mycorrhizas?,Biological
19、 control of Dutch elm diseaseDutch TrigA suspension of live spores of the fungus Verticillium dahliae injected into the tree by gouge pistol. Protects by inducing resistance in the treeProsSmall injection holes, rapid, less costly than fungicideConsMust be applied every year V. dahliae is a plant pa
20、thogen Only an option before infection,5. QUARANTINEExcluding diseased plants, seeds, bulbs or contaminated soil, machinery, etc.Introduced pathogens Sudden oak death,The current host list includes: California black oak, coast live oak, Shreve oak, tanoak, rhododendron, California bay laurel, big le
21、af maple, madrone, manzanita, huckleberry, California honeysuckle, toyon, California buckeye, California coffeeberry, Douglas-fir and coast redwood and Arrow wood (in Germany,the United Kingdom, and the Netherlands).,SUDDEN OAK DEATHControlled largely by quarantine and plant destruction,6. DOING NOT
22、HINGHow much disease are you prepared to handle?Decay in trees could provide wildlife habitat, but could allow development of hazard trees,PNW Plant Disease Management Handbook,For each host Cause Symptoms Cultural control Chemical control References,Cherry brown rot in Arboretum,Brown rot mummies,C
23、herry brown rot,Cause two fungal species (Monilinia fructicola and M. laxa)incites blossom blight, twig and branch dieback, fruit rot of ornamental and fruit trees cherries, peaches, nectarines, prunes, plums, almonds and apricots. More of a problem west of Cascade crest. Wind and rain blow ascospor
24、es and conidia to healthy blossoms in spring from mummies.,Cherry brown rot continued.,Symptoms Infected flower parts turn light brown or gray; water soaked flowers; branch girdling; profuse gumming; fruit symptoms dark spots with buff-colored spores,Brown rot continued,Cultural control Remove and c
25、ontrol infected twigs and branches a Remove and destroy mummified fruit Use moderate amounts of N fertilizer,Brown rot continued,Chemical control Apply fungicides during the bloom period at early popcorn, full bloom, and/or petal fall with alternate fungicides 26 different fungicides are availableCaptan 80 WDG ar1.9 to 2.5 lbs/acreFixed copper for blossom blight onlyWettable sulfur,
