PESTS OF ORCHARD AND FRUIT GARDEN. 



4$ 



The mycelium sends suckers into the epidermal cells of the leaf whence 

 to obtain nourishment. Subsequently to its appearance on the leaves the 

 mildew spreads afterwards into contact with the fruit. 



Later in the season the second form of fruit is developed, after the 

 manner of the Rose mildew, Pea mildew, and others of its kind. These 

 are in the form of minute globose conceptacles, which become dotted 

 over the mycelium, each containing a single ascus which encloses eight 

 sporidia. 



These conceptacles are only sparingly produced, and those generally 

 occur on the petioles of the leaves, and, like those of the vine mildew, 

 perhaps in this country not at all. Doubtless the mildew is increasing 

 with us, and complaints are being heard of it in Strawberry-growing 

 localities. Some varieties stand the chances much better than others. 



Predisposing circumstances are affirmed to be sudden changes of 

 temperature, especially a decrease during the night or a cool temperature 

 followed by sunny weather. 



Experiments made by two fungicides seemed to afford satisfaction, 

 viz. (1) one ounce of carbonate of copper and five ounces of carbonate 

 of ammonia dissolved in a quart of hot water and then mixed with 

 sixteen gallons of water when cold. (2) Dissolving a quarter of an ounce 

 of sulphide of potassium in a gallon of water. Spraying with either of 

 these mixtures is therefore recommended, especially the first ; but promp- 

 titude must be used whilst the mildew is on the leaves, since it is useless 

 when it has obtained a hold upon the fruit to attempt to save the crop. 



Sacc. SyU. i. 8; Cooke Hdbk. No. 1911; Berk. Gard. Chron. 1854, 

 p. 236 ; Journ. B.H.S. xxv. (1900), p. 132, figs. 35, 36. 



EXPLANATION OF PLATES X., XL, XII. 



Fig. 1. — Septoria pip-kola, Desm. — .Spotted leaf, section of perithecium and spornles 

 x 400 L 



2. — Oidium farinosum, Cooke Young leaves with mould ; chains of conidia, and 



free conidia x 400. 



3. — Fusicladium dendritic um, Wallr.— On Apple with threads and conidia x 400. 



4. — Ghvosporium fructigenum, Berk. — Spots on Apple with conidia * 400. 



5. — Botryodiplodia pyrenophora, Sacc. — On Apple twig; a, young conidia; 



b, mature conidia. * 400 



6. — Nectria ditissima, Tul. — Forming canker on branch ; a, fissure showing 



fungus ; b, perithecia, magnified ; c, sporidia x 400. 



7. — Valsa ambiens, Fr. — Pustules on branch; a; conidia oozing in a tendril; 



b, conidia x 400 ; c, asci and sporidia x 400. 



8. — Raestelia canccllata, Peb.— On Pear leaf, with receptacle and spores. 



9. — Exoascus bullatus, Tul. — On Pear leaf, with ascus and sporidia .< 400. 



10. — Entomosporium maculatum, Lev. — Spotted leaf with conidia x 400 



11. — Fusicladium pirinum, Lib. — On Pear leaf, with threads and conidia x 400. 



12. — Monilia fructigena, Pers. — Tufts of mould on fruit; a, section of tuft; 



6, thread and conidia x 400. 



13. — Exoascus pi uni, Fckl. — Diseased fruits; a, asci with sporidia x 400. 



14. — Polystigma rubra, Pers. — On Sloe leaf; a, section of blotch; b, conidia; 



c, ascus and sporidia x 400. 



1-5. — Puccinia pruni, Pers. -On Plum leaf; a, uredospores ; 6, teleutospores x 400. 

 lb.—Poclospha>ra tridactyla, Wall. — Conceptacle with fulcra, enlarged; a, ascus 

 and sporidia x 400. 



17. — Uncinula prunastri, DC. — Leaf with mould, and conceptacle, enlarged ; 



a, tip of appendage ; b, ascus and sporidia x 400. 



18. — Cladosporium epiphyllum, Link. — Nodules of gum on twig. Threads and 



conidia x 400. 



