Chrysanthemum pest and diseases

Pests and Diseases of Chrysanthemum:
Chrysanthemums are not prone to a great many plant pests and diseases, and in some seasons, in fact, they are hardly troubled at all.

1. Pests and Diseases of Chrysanthemum PERUMAL, R. 2016603110 M. Sc., Floriculture & Landscaping

2. About Chrysanthemum… Dendranthema × grandiflora Asteraceae , n=9 Europe and Asia Queen of East, Autumn Queen, Glory of east, guldaudi , Pot Mum National flower of Japan Chrysanthemum city: Ju -Xian (China ) Head / Capitullum , Ray & Disc florets Short day plant – ‘Photo sensitive’ Sensitive to water-logging Terminal cuttings and suckers Planting : April-May 15 x 15cm (45 plants / m 2 ) NPK @ 20:20:10 g / m 2 Pinching & Disbudding Yield: 270 sprays / m 2 2% sucrose + 1200-4800 ppm AgNO 3 increased the vase-life from 12 to 20 days Quilling of petals, Petal bum (B deficiency), Bleaching of petals

3. Chrysanthemum Pest Aphids Thrips Leaf Folder Leaf Miner Bud Borer Red Spider Mite Diseases Rust Powdery Mildew Septoria Leaf Spot Alternaria Leaf Spot Verticillium Wilt, Fusarium Wilt Grey Mould Flower Blight Root Rot Bacterial Blight

4. Pests

5. Aphids Myzus persicae , Macrosiphoniella sanborni Suck the cell sap from growing shoots & lower surface of leaves Greenish – black nymphs Chocolate – brown adults Loss of vigour Yellowing Premature leaf fall Stunted growth of plant Honey dew black sooty mould Adults Sucking plant fluids from veins Inhibits photosynthesis by reducing amount of light reaching the leaves

6. Aphid infestation on leaves and flower of chrysanthemum

7. Management: Spray Pongamia or neem oil at 20ml/l 4% Pongamia kernel extract at 10-15 days interval Spray Dimethoate 30 EC @ 2ml/l Oxydematon methyl 25 EC @ 2ml/l Acephate 75 SP @ 0.5 g/l Application of Verticillium lecanii @ 3 g/l Release of I day old Chrysoperla carnea larvae @ 50:1 ratio eliminated aphid population (Scopes, 1969)

8. Thrips Microcephalothrips abdominalis , Frankiniella spp., Thrips spp. Silvering Mottling Distortion of leaves Damaged flowers: Discoloured Withered & dried scorching Slender white nymphs & Black adults Feed on tender leaves Rasping & sucking mouth parts Cannot penetrate deep into plant tissue Found throughout year Female thrips live: 30 – 40 days (150-300 eggs) Spreading tomato spotted wilt virus

9. Thrip damage on flowers of chrysanthemum

10. Management: Spray Dimethoate 30 EC @ 2ml/l at 15 days interval Severe, spray Ethofenprox 10 EC @ 1ml/l Fipronil 5 SC @ 1.5 ml/l Covering of young buds with polythene bags with holes prior to blooming protects flowers from attack by thrips (Wang & Lin, 1984).

11. Leaf Miner Liriomyza trifolii Severe in March – June Larvae feeding on mesophyll leaving characteristic trails Severaly damaged leaves, show extensive mining which turn brown and dry up Leaf miner infestation on chrysanthemum leaf

12. Management: Remove and destroy Spray Triazophos 40 EC @ 1.5 ml/l Abamectin 1.9 EC @ 0.4 ml/l Spray with Dichlorovos 76 EC @ 1 ml/l Decamethrin 2.8 EC @ 1 ml/l Dipping of chrysanthemum cuttings in 3% Margosan ( neem formulation) for 2 hrs and foliar spray of the same botanical @ 0.4% reduce the pupae & adults ( Lindquest et al., 1986) Install yellow sticky traps coated with Chlopyriphos 20 EC @ 2.5 ml/l to trap adult population Adults Larvae

13. Bud Borer Helicoverpa armigera (Nocturnal moths) Feed on very young terminal shoots Young foliage & Flower buds and heads. Evidence: round holes in buds & flower heads Bud worm larvae Feed for 2 – 3 weeks in warm weather Eaten enough, they leave plant & burrow in soil – pupate. Adult moth Each female lay up to 1000 eggs deposited on new leaves. Larvae tunnels its way into the buds and feed on developing flower parts

14. Bud Borer infestation on chrysanthemum Management: Collection & killing of grown up larvae NSKE 4% / neem oil 1% sprays Spraying Methyl parathion 0.05% Ethofenprox @ 0.01%

15. Red Spider Mite Tetranychus urticae Red Spider Mite is a profuse web-spinner in its active stages Mite colonies, seen on upper surface of leaves Damage starts in March & reaches peak during April - J uly Affected leaves, discoloured wilt and fall off damaging shoots dry up

16. Management: Removing and burning of infested shoots Spray Dicofol 18.5 EC @ 2.5 ml/l Dimethoate 30 EC @ 2 ml/l Profenophos 50 EC @ 1 ml/ l Spray with Pongamia / neem oil @ 1%

17. Diseases

18. Septoria leaf spot Septoria chrysanthemi Symptoms: Lower leaves are infected first Spots: first yellowish then become dark brown & black Severe infected leaves are prematurely wither & drop off from the plant Disease develops rapidly in cool wet weather Spores of fungus are spread by splashing water

19. Management: Regularly clean up & destroy debris Avoid splashing water into plant foliage Spraying of 0.1% Carbendazim ( effectively control) Fungicides: Chlorothalonil Mancozeb Myclobutanil Thiophanate methyl Capton

20. Alternaria Leaf Spot Alternaria spp. Symptoms: Pathogen cause small dark brown spots with yellow surroundings. Spots merge & leaves begin rot. Severe infection results, withering of leaves dead leaves hanging to the stem Finally death of the entire leaf Management: Spraying Mancozeb / COC each @ 2 g/l

21. Wilt Verticillium albo-atrum Symptoms: Foliage becomes yellow & wilted Leaves begin to die from the base of the plant upward Stems may exhibit dark streaks in the vascular system Infected plants, stunted & fails to produce flowers Favored when cool weather is followed by hot.

22. Management: Pathogen - free cuttings Use resistant cultivars Continuous cropping in sick soil should be avoided. Soil drenching with 0.2% Carbendazim Avoid susceptible cultivars: Echo Glowing Mandalay Mountain peak Paragon Pert Wedgewood

23. Fusarium Wilt F usarium oxysporum var. trachaephilum Symptoms: Yellowing of foliage, stunting and wilting Stems show reddish brown discolouration of vascular system Fusarium is spread in contaminated soil & from infected cuttings and is favored by high temperature, high RH, over watering & poor drainage

24. Management: Pathogen - free cutting & pasteurized growing media Adjust pH 6.5 – 7.0 Use of nitrate nitrogen fertilization Avoid susceptible cultivars: Bravo Orange bowl Royal trophy Yellow delaware

25. Grey M ould Botrytis cinerea Symptoms: O ccur on petals, leaves or as a stem canker as brown, water soaked spots. Infected plant parts covered with grey to brown, powdery masses of spores. Senescing tissues are most susceptible Favored by extended periods of cloudy, humid & weather.

26. Management: Practice good sanitation Avoid wetting flowers when watering & do not over crowd the plants Provide good air circulation Keep humidity low by combination of heating & venting Fungicides: Chlorothalonil Mancozeb Fenhexamid Thiophanate methyl

27. Flower Blight Stemphylium lycopersici S ymptoms Infection is noticed on calyx & petals in the form of necrotic brown spots. Infected flowers wither & die Causes small, necrotic, light brown to dark brown lesions (cause blossom death) Favored by wet conditions & temperatures between 60⁰-85⁰F Management Rouge & dispose of infected plants Provide good air circulation Avoid overhead irrigation & keep plants dry Spraying 0.1 – 0.2% Mancozeb / 0.1% Benomyl

28. Powdery Mildew Erysiphe cichoraceum Symptoms White to ash – grey powdery growth on leaves & stems Foliage become puckered or disorted Infected leaves will shrivel & die Most serious during hot, humid weather Management Proper plant spacing Good air circulation & Low RH, adequate light levels Apply fungicides: Myclobutanil Triadimefon Potassium bicarbonate Thiophanate methyl

29. White to ash – grey powdery growth on leaves

30. Rust Puccinia chrysanthemi , P uccinia horiana Symptoms Puccinia chrysanthemi : Minor damage Defoliation and reduced flower production Puccinia horiana : White rust Green house crops Whitish yellow to green lesions on upper leaf surfaces Rust results, leaf distortion discolouration defoliation & plant death Management Infected plants to be destroyed Resistant varieties: Achievement Copper Bowl Miss Atlanta Powder Puff Orange Bowl

31. Pustules of chrysanthemum white rust on lower surface of chrysanthemum leaf.

32. R oot Rot Pythium spp ., Phytophthora spp . Symptoms: Infected plant parts (root, stem & leaves) Management: Good drainage conditions to prevent logging Soil drenching with Mancozeb @ 2 g/l

33. Bacterial Blight Erwinia chrysanthemi Symptoms: Water soaked lesions & Pith becomes jellylike Death of buds & stems & Blackening of terminals & wilts Favored by high temp. & RH Management: Use disease free cuttings Dip in streptomycin Reduce humidity

34. Nematodes Lesion Nematode Bud and Leaf Nematode Root – Knot Nematode Sting Nematode Lesion Nematode, Pratylenchus chrysanthus Edward et al.,( 1969) Common above ground symptoms Reduce flower size Management: Application of neem cake enriched with T. harzianum @ t/ha Root – Knot Nematode, Meloidogyne spp. M. a renaria & M. javanica have been reported on chrysanthemum ( Chandawani et al., 1967)

35. Bud and Leaf Nematode Aphelenchoides ritzemabosi , (Gill & Sharma, 1976) Interveinal discolouration Infested leaves shrivel, hang down as the leaf dies. The nematode escape through stomata & migrate in surface water films to infect terminal flower buds which produce deformed and under sized blossom. Dipping of chrysanthemum stools in 0.03% Parathion for 20 mins. Hot water treatment (48⁰c for 5 mins)

36. Reference Integrated Pest and Disease Management in Horticultural Crops, P. Parvatha Reddy Advanced Commercial floriculture, S.K. Battacharjee and L.C. De Production Technology of Commercial Flowers, L.C. De

37. Thank you…