THE EEPOET OF THE No. 36 



As Pests of Vegetable Crops. 



Only a few species have been found, but the enormous numbers of individuals 

 make up for the fewness of the species. Myriads of Tetranychids are found feed- 

 ing on the leaves, and the Tyroglyphids are everywhere present on the stored roots. 

 Tetranychus telarius is the most common species on the outside crop, and Tyro- 

 glyphus longior and Gamasids are most troublesome inside. 



As Pests of Shade Trees and Ornamental Shrubs and Herbs. 



Scarcely a tree or shrub escapes the attacks of one or more of these species. 

 Some indeed, such as the maples, have as many as twenty-five or more species, 

 feeding and absorbing nourishment from the leaves, twigs, bark, stem and roots. 

 ]\Iost of the injuries of the trees are due to species of the Eriophyidse, but in 

 case of the shrubs and herbs the Tetranychids do most damage. The type of injury 

 on the trees takes the form of galls. These are beautiful structures and at certain 

 seasons of the year where they are not too abundant, appear more ornamental than 

 destructive. As examples of these might be mentioned the Top Gall of the Soft 

 Maple, the Pocket Gall of the Basswood, the Frost Gall (Erineum) of the Maple 

 and Beech. On the shrubs we find the Tetranychus species again in evidence — the 

 Privet, Garden Bell, Lilac, Spirea, Eoses and Dogwoods. Among the ornamental 

 herbs that suffer most from the attacks of Tetranychids are the perennial Phlox, 

 Petunias, Nasturtium and Malva. 



As Pests of Forest Trees. 



The Ontario forest flora affords suitable hosts for over fifty species of 

 gall-making mites. A few of the more important ones have been discussed 

 under Shade Tree Pests, but a large number of the species are not met with 

 except on forest trees. These variously shaped galls are found on the flowers, fruits, 

 leaves, twigs, and stems of such trees as the Elms, Poplars, Willows, Oaks, Chest- 

 nuts, Hawthorns, Maples, Lindens, etc. They not only do injury to the develop- 

 ment of the tree but cause unsightly vegetable deformities sometimes literally 

 covering the tree. The Witches Broom of the Hackberry, Willow, etc., is also 

 the result of the work of these mites. Much difficulty is experienced in treating 

 the trees for these pests as they are protected by the tissue of the gall which forms 

 around them. The lime-sulphur wash which is found most effective for the Pear- 

 Leaf Blister mite is about the best remedy where it is practicable to spray. Eed 

 Spiders of the Tetranychus genus almost equal the Eriophyes in abundance on 

 forest trees. Only a few species have been determined but the excessive numbers 

 of these species which are found make up for the fewness of the species. When 

 closer study is made of this genus, it is altogether likely that a far larger number 

 of species will be discovered. Tetranychus spinosa, which is found on the Linden 

 on the upper side of the leaves is often sufficiently abundant to consume the whole 

 of the chlorophyll, changing the appearance of the tree from green to yellow in 

 midsummer. Tetranychus hicolor produces the same effect on leaves of Oaks and 

 Hawthorns as T. spinosa does to the Linden. T. telarius is also found on the leaves 

 of many forest trees. 



As Greenhouse Pests. 



The florist is only too familiar with the work of the Eed Spider and the Bulb 

 mite, which are invariably present in large numbers attacking most of his flower- 



