The Plant Doctor in the Flower Garden 



From Material Prepared by Dr, F. D. Heald, Professor of Plant Pathology, Washington State Agricultural College 



[Editor's Note: This is something new in the way of "spraying tables/' covering both insects and disease of the ordinary plants of the garden. In 

 all the multitude of books on the subject not one has in a handy form anything like as comprehensive a survey to fit the needs of the common garden 

 flowers and ornamental plants. Many tables deal with fruit and vegetables pretty thoroughly, but are of little use about the flower beds, lawns, etc. 

 To meet this need we have gathered the available matter in a way never before presented. Unfortunately, knowledge is still lacking about certain 

 diseases, and so the reader will undoubtedly not find answers to all his questions (Larkspur "blacks" for instance). Very many troubles are "general" 

 and are discussed as a group first of all. The reader should familiarize himself with them at the beginning, and then follow through the alphabetical 

 list of plants for any special feature not covered by the "general " groups. The diseases of tree and shrubs generally (including those of Roses) have been 

 omitted equally with those of vegetables and fruits available elsewhere. These can be presented at some later date if our readers want them.] 



DESCRIPTION OF TROUBLE 



GARDEN PLANTS IN GENERAL (Insects) (See also "red spider" 

 and "white fly" under greenhouse insects 



Yellowish, dark-spotted worms (5- f inch) spin webs over plants 

 and skeletonize leaves 



Young plants cut oflfevcn with the surface of ground or little higher 



Leaf eating caterpillars not protected by web 



Foliage riddled with holes by a small (one-eighth inch) cream-col- 

 ored beetle with striped wing covers 



Slate gray or shiny black beetles on leaves and flowers 



Roots showing various enlargements with streaks or spots of in- 

 ternal dark tissue 



Plump white grubs feed on the roots and cause more or less in- 

 jury 



Seeds, germinating seeds and young seedlings injured or destroyed 

 by slender, yellowish-brown shiny larvae 



Green or brownish caterpillars frequently moving in great numbers 

 and devouring the vegetation in their path 



Minute, brown or black, jumping beetles (one-twentieth — one- 

 twelfth inch) eat small irregular holes (larvae feed on roots) 

 GREENHOUSE PLANTS IN GENERAL (Diseases) 



White powdery growth covering leaves or stems 



Seedlings drop over and die 



Cuttings rot without rooting • 



Black meld growing over surface of leaves 



GREENHOUSE PLANTS IN GENERAL (Insects) 



Minute, dark-bodied (one-fifteenth inch), or yellowish (one-twenty- 

 fifth inch) insects working on under surface of leaves; no webs 



Very fine webs on under surface of leaves or over flower heads 



Active, white-winged insects (one-tenth inch) working mostly on 

 under side of leaves, causing yellowing 



Slow-moving, soft-bodied bugs (one-sixth inch) covered with whit- 

 ish powdery secretion 



Greenish or dark soft-bodied insects on leaves or succulent stems 



Oblong, slate-gray (one-eighth-one-half inch) "bugs'* with seven 

 pairs of legs; roll up when disturbed 



Whitish caterpillar, with median green stripe (three-quarter inch) 

 folds leaves or ties them together with silk 



Active greenish or reddish caterpillars roll up leaves, fasten them 

 with silk and feed within 



Buds of various plants eaten but no insects evident (Feeding done 

 at night) 

 SEEDLINGS (Disease) 



Seedlings drop over, wilt and die; brown rotted areas on stem at 

 about ground level 



(Insects) (See especially wtreworms, cutworms and flea- 

 beetle in Garden Plants) 

 ASTER (Diseases) 



Wilting and death of plant, stem rotted at or below ground 



Yellowing of leaves, followed by wilting and death; brown fungous 

 threads on roots or basal part of stem 



Foliage yellowish, leaves more or less crinkled or puckered 



Orange-red spore dots on leaves — (Peridermium stage on Pines) 

 AZALEA (Diseases) 



Brown spots on foliage 



Small, crowded, orange spore dots on under side of leaves 

 BLUEGRASS (Diseases) 



Dark enlarged spurs replacing some of the sesds 



White powdery coating on the leaves 



Reddish or black spore pustules on stem and leaves 

 Moldy coating around stem, parts above wilting 



(Insects) 

 The flower panicles wither before they have become fully expanded 

 CALLA (Diseases) 



Rotting near the surface and progressing up or down; affected tis- 

 sue soft and watery 

 Leaves spotted: 



Spots ashen gray with numerous black spore fruits 

 Spots, dark and circular 

 CANN'A (Diseases) 



Leaves showing small, powdery, brown or orange spore-dots 

 CARNATION (Diseases) 



Stem and roots showing brown fungous threads on their surface 

 Brown fungous threads absent 



Flower buds rotting without opening or imperfectly opened and 

 base of petals rotted; "seed-like" mites within 

 Buds rotting without opening, producing a gray powdery mold 

 Calyx split, floweis imperfect, but no rot 



Circular spots bearing concentric rings of dark mold on leaves, 



stems and sometimes calyx 

 Spore-dots on leaves round or elongated parallel to the length of 



leaf, brown and powdery 



Leaf spots oblong, blanched or pinkish, bearing numerous central 



black spore fruits 

 Leaf and stem spots ashen white with black mold in centre 

 Affected parts pale, studded with numerous, minute, black, spiny 



spore fruits 



CHRYSAVI HEMUM (Diseases) 



White powdery spots on green parts leaves spotted or blighted: 

 Large brown or black blotches, with indefinite border, often en- 

 larging to include whole leaves 



Spore dots brown, powdery (one-sixteenth — one-eighth inch); 

 seriously affected curl and die . 



Ray flowers blighted, flowers imperfect 



{Insects) (See: also greenhouse insects, 

 Minute grubs make iiregular twisting mines within the leaves; in- 

 fested plants disfigured and sickly 



NAME 



CAUSE OF TROUBLE 



REMEDY 

 REFERENCE 



Garden web-worms 



Loxostege moth 



11,29 



Cut-worms 



Various moths 



37, 33 ' 



Caterpillars 



Various moths 



11,12 



Pale-s t r i p e d flea 







beetle 



Systena taeniata var. blanda 



5 with 11 



Blinker beetles 



Species of Meloidae 



11, 12 



Root-knot or nem- 



Heterodera radicola 



35 



aodes 







White grubs 



Lachnosterna spp. (May beetles 

 or June bugs) 



30,29 



Wireworms 



Elaterdiae (Various click 

 beetles) 



30,29 



Army worm ' 



Various moths 



39, 11 or 

 37,33 



Flea-beetles 



Epitrix cucumeris and others 



5 (5-5-5o) 

 or add 11 



Powdery mildew 



Sphaerotheca, Erysiphe 



40 



Damping-ofF 



Various fungi 



3 or 4 



Damping-ofF 



Various fungi and bacteria 



3 or 4 



Black mold 



Meliola spp. 



Control 

 white fly 



Thrips or stigmon- 



Heliothrips haemorrhoidalis, 



18,22 



ose 



Thrips tabaci 





" Red spider" 



Tetranychus telan'us 



19, 17 or 10 



White flies 



Aleurodes spp. 



21 



Mealy bugs 



Pseudocscus spp. 



15 or 21 



Plant lice 



Myzus persicae and others 



18 



Sowbugs 



Porcellio laevis 



21, 37, 33, 



Greenhouse leaf-tier 



Phylyctaenia ferrugalis 



40 or 11 



Oblique-b a n d e d 



Archips rosaceana 



40 or 11 



leaf-roller 







Climbing cut worms 



Various moths 



37 



Damping-ofT 



Rhizoctinia sp., Pythium de- 



2, 32 (air- 





baryanum and other fungi 



slaked) 



Wilt or stem-rot 



Fusarium sp. (Imperfect) 



2,3,4,28 



Root-rot 



Rhizoctinia sp. 



See carna- 

 tion 



Yellows % 



Non-parasitic 



25 



Rust 



Colesporium souchi 



5 



Leaf spot 



Septoria azaleae 



8,12 



Rust 



Pucciniastrum minimum 



Not severe 



Ergot 



Claviceps sp. 



36,28 



Powdery mildew 



Erysiphe graminis 



10, on shad- 

 ed lawns 



Rust 



Puccinia spp. 



Not serious 



Cat-tail fungus 



Epichloe typhina 



Not serious 



Silver top (Mite) 



Pediculopsis gramineum 



27 



Soft rot 



Bacillus aroidae 



42 (corms); 

 28 



Leaf spot 



Phyllosticta richardiae 



7 



Leaf spot 



Cerospora richardiaecola 



7 



Rust 



Uredo cannae # 



Not serious 



Rhizoctinia 



Rhizoctinia sp. 



25,3 



Wilt 



Musarium sp. 



2,53 



Bud-rot 



Sporotrichum poae 



26, 24, 33, 

 43; 



Bud-rot 



Botrytis spp. 



24,33 



Split calyx 



Non-parasitic 



31 



Band calyx 



Fairy ring 



Heterosporium echinulatum 



24, 5, or 7 



Rust 



Uromyces caryophyllinue 



34, 43, 42; 



43, 42 



(Cuttings) 



Leaf spot 



Septoria dianthi 



34, 5, or 7 



Leaf spot 



Alternaria dianthi 



34, 5, 7,43 



Anthracnose 



Volutella dianthi 



2 (Cuttings), 

 33 



Powdery mildew 



Erysiphe cichoracearum 



10,40 



Leaf spots or blight 



Septoria chrysanthemi; Cylin- 



6, soap for 





drosporium chrysanthemi 



sticker; 

 26 



Rust 



Puccinia chrysanthemi 



36 (cut- 

 tings), 26 

 34 



Ray blight 



Assochyla chrysanthemi 



5,24 



Chrysanthemum leaf 



Phylomyza chrysanthemi 



18, I-400 



miner 







REMEDIES IN DETAIL 



T^HIS is a novel presentation of the recom- 

 ■*• mended remedies. They are classified in 

 groups and the reference numbers correspond to 

 the figures in the accompanying table. Particu- 

 lar attention should be paid to general meth- 

 ods of control and sanitation through giving the 

 plants conditions in which they can grow prop- 

 erly. Many of the pests and diseases are the 

 direct results of improper environment. 



Seed Treatment 



1. Formaldehyde Steep. The seed is soaked or dipped in a 

 solution of commercial formaldehyde or formalin (40 per cent, solu- 

 tion) in water for a definite length of time. The strength of the 

 solution and the time it is allowed to act on the seed must be given 

 most careful attention. One pint of commercial formaldehyde to 

 40 gallons of water (a "1 to 40 solution") is a common strength. 

 Formalin solutions lose their strength quite rapidly on standing. 



Soil Sterilization 



2. Surface Firing, (a) Direct firing: A layer of straw, brush, 

 or other litter is spread over the seedbeds in the open and burned. 

 In carrying out this treatment, the seedbeds should be prepared 

 for planting before burning the litter, after which the ashes may be 

 raked into the surface soil. The ground is then ready for planring, 

 and the upper layers should be free from objectionable organisms. 



(b) Pan firing: For this method a sheetiron pan, 3 by 9 feet, is 

 employed. Support it over the bed to be sterilized and build a fire 

 beneath. Next shovel the surface 6 inches of soil from the next 

 3x9 foot strip into the pan and heat for an hour. Return this soil 

 to its original position and treat a similar area from the other side of 

 the pan. Next move the pan on and continue the process. 



3* _ Steam Sterilization. (Adapted for greenhouse work or for 

 beds in the open when live steam is available.) 



(a) The perforated-pipe method. Permanent or movable perfor- 

 ated pipes may be arranged in greenhouse benches. A 2-inch main 

 from a boiler furnishing 80 to 100 pounds pressure should be con- 

 nected to a set of 1 2-inch pipes placed at a depth of I foot, spaced 

 12 to 18 inches apart and provided with one eighth to one fourth 

 inch perforations every 6 to 12 inches. The initial cost cf perman- 

 ent pipes is high, but their operation requires little labor and they 

 may be used for subirrigation if desired. Place the pipe in posi- 

 tion and fill in the. soil and fertilizer (except commercial fertilizer) 

 and have the seedbed prepared as if for planting. Cover with canvas 

 or tarpaulin and turn on the live steam for 1 to 2 hrs. 



(b) The inverted-pan method. This has proved practical for 

 extensive work in the open and has been successfully employed for 

 the treatment of tobacco seedbeds. The apparatus consists of a 

 sharp-edged, galvanized iron pan 6 to IO feet and 6 inches deep, 

 fitted with handles for convenience in moving, and provided with 

 an intake for the attachment of a steel hose. In practise the pan 

 is inverted over the soil to be sterilized and the edges forced into the 

 ground to prevent the escape of steam which is then turned in. 

 The temperature is maintained at 175 to 180 degrees F. for 1 to 

 2 hours. Successive areas may be treated in this way until the en- 

 tire seedbed has been covered. In sterilizing seedbeds by steam, it 

 should be borne in mind that lighter soils are more easily sterilized 

 than heavy ones. Also that soils high in humus are liable to injury 

 by over sterilization. Soils can be most efficiently sterilized when 

 they contain a medium amount of water. 



4. Application of Fungicide. This may be distributed (in 

 solution) from a sprinkling can, a spray pump, or by one of the over- 

 head watering systems. In all cases the ground should be spaded 

 or plowed and put into shape for planting previous to the applica- 

 tion of the fungicide. 



(a) Drenching with formaldehyde. Apply a solution of commercial 

 formaldehyde, 3 pints to 50 gallons of water, at the rate of seven 

 eighths gallon to 9 square feet, cover with canvas for 24 hours and 

 air for one week before seeding. Ground intended for early spring 

 planting may be sterilized in the late fall if more convenient. 



(b) Sulphuric acid drench. Apply three sixteenths ounce of com- 

 mercial sulphuric acid (in water) per square foot of soil at the time 

 of seeding. Possible injury to seedlings may be greatly reduced by 

 abundant watering during the germination period. This method 

 is especially applicable to the treatment of seedbeds used for grow- 

 ing Pines or other evergreens. 



(c) Sulphur. Flowers of sulphur or sulphur flour may be broad- 

 casted and then wotked into the surface soil just before planting 

 at the rate of 350 to 900 pounds per acre. This soil is of particular 

 value in treating land badly infected with the organisms causing 

 potato scab. 



Spraying 



5. Bordeaux Mixture: Take Copper sulphate (bluestone), 

 4 pounds; Quicklime, S pounds; Water 50 gallons. Prepare 

 stock solutions of both the copper sulphate and the lime of such 

 strengths that each gallon will contain 1 to 2 pounds of one or the 

 other of these substances. Protect from evaporation or dilution 

 by rains, and always stir before using. Dissolve copper sulphate 

 either by suspending it in a coarse bag in the water or by using hot 

 water. In using the stock solutions, measure out the right amount 

 of each to give the desired number of pounds of chemical and dilute 

 with half the quantity of water in separate (wooden) vessels. The 

 two diluted solutions should then be poured together through a 

 copper sieve (about 20 meshes to the inch) to exclude small solid 

 particles. Bordeaux should always be freshly made each time, as 

 it becomes weak on standing. The mixture may be tested to see 

 it does not contain an excess of copper by adding a few drops of a 

 IO per cent, solution of potassium ferro-cyanide (yellow prussiate 

 of potash). If the drops make a brown sediment appear in the 

 bordeaux, add more lime. 



6. Resin-Bordeaux. Bordeaux, any strength, 48 gallons; 

 Resin "sticker", 2 gallons. The resin "sticker" is made by melting 



iu 



