Insect Pests and Fungoid Diseases. 



411 



which have one pair of legs each, whilst the remainder have each two pairs 

 of legs close together at the bases ; the antennae is short. The centipedes 

 may be distinguished from millipedes by generally having flattened bodies, 

 brownish in colour, each segment having only one pair of legs, and their 

 antennas are longer. 



Treatment: On small areas injections of carbon bi-sulphide may be 

 used to kill the millipedes in the ground. Traps of pieces of mangold, 

 scooped out and buried an inch or two below the surface of the soil will 

 attract them, when they may be caught and killed ; or pieces of cabbage 

 leaf dipped in a solution of arsenate of lead and laid about on infested 

 ground will poison many of them. All ground in which they are present 

 should receive a good dressing of quicklime or gas-lime. 



RED SPIDERS (Tetranychus, &c.) These mites, variable in colour, 

 are difficult to see with the naked eye. Their presence on plants is indi- 

 cated by a yellowish scorched appearance of the leaves. They flourish 

 most in a dry arid condition of the atmosphere, and are therefore most in 

 evidence in greenhouses or frames which have been allowed to get too dry, 

 or on fruit trees on walls or in other dry situations, and especially on 

 plants in shallow soils in a droughty season. 



Treatment: The most obvious thing in dealing with greenhouses or 

 frames or other confined spaces is to take measures to prevent an attack, 

 by maintaining sufficient moisture at the roots and amongst the foliage. 

 When the attack is slight frequent and forcible spraying with clear water 

 is often sufficient to eradicate it. In more decided cases paraffin emulsion 

 may be used (but not on cucumbers or melons) or potassium sulphide and 

 soft soap. Before spraying, leaves badly attacked should be carefully re- 

 moved and burnt ; the mites are very active and if shaken off the leaves 

 will speedily climb on to the plants again, therefore it is a wise precaution 

 to place badly-infested leaves immediately in a pail with a little paraffin at 

 the bottom. The mites cover the underside of infested leaves with a fine 



web, which makes it diffi- 

 cult to reach them with 

 insecticides, therefore a 

 considerable amount of 

 force must be used in 

 spraying. 



SLUGS and SNAILS. 



Of these there is a num- 

 ber of varieties, some with 

 shells and some without. 

 They are very destruc- 

 tive to green vegetation, 

 particularly so to tender 

 seedlings, large numbers 



f whidl the wil1 COttl - 



1, Grey Field Slug, Limax agrestis 2, Black Slug, Lima* 

 ier (less than life size); 3, Limax (Her in repose; 4, Eggs, pletely destroy in a short 



