75o 



The Bulb Mite. 



[march, 



are five-jointed, bearing spines and hairs, and ending each in a 

 single claw. The male has the abdomen more rounded at the 

 end than the female ; the hind part of the cephalo-thorax in the 

 male is as wide as the abdomen ; in the female it is not quite 

 so wide. In one of the two forms of male the third leg on 

 each side is thicker, and is not used in locomotion. The 

 hypopus carries on the middle of the under surface of the hind 

 region a horny plate with twelve suckers ; in front of this plate 

 are two additional suckers. 



The mites are extremely minute — it may be less than one- 

 twentieth of an inch — and need for their examination a good 

 lens or microscope. 



Life-History. — From the eggs hatch out six-legged larva?. 

 After feeding for a short time the larva becomes inert and 

 moults ; the new form has eight legs, and is known as a 

 nymph. In the nymph stage the greatest growth takes place. 

 In ordinary circumstances the nymph — according to Michael's 

 experiments — probably moults twice, each moult being preceded 

 by a sluggish period ; the last moult of the nymph is succeeded 

 .by the sexually mature adult. Where, in the life-history of the 

 individual, a hypopial stage appears, the number of moults is 

 greater than the above. Larva, nymph, and adult do not 

 greatly differ from one another in external appearance, 



Treatment. — I. This pest is very difficult to combat because 

 the extremely tiny mites feed not only on the outside of the bulbs 

 but they exist between the leaf scales of the bulb, feeding and 

 laying their eggs in the interior, where they can scarcely be 

 reached. The best plan is to burn infested bulbs, and the soil, 

 whence these have been removed, should be disinfected. 



2. Wash or spray the bulb with paraffin, the treatment being 

 repeated a fortnight later. 



3. Washing the bulbs in sulphide of potassium (liver of 

 sulphur), 1 oz. to 5 gallons of water, or brushing with this after 

 removal of the outside loose scale leaves. This treatment is 

 useful against fungi which follow the attack of the mite. 



4. Fumigating with bisulphide of carbon. The bulbs to be 

 treated should be placed in an air-tight receptacle, and a saucer, 

 into which bisulphide of carbon has been poured, placed on the 

 top of them. The bulbs should be left in the vapour for forty- 



