170 HOUSE PLANTS 



soon as it is detected, shake the soil from 

 the roots, and thoroughly wash them in 

 clean water, repotting in a clean pot and new, 

 clean soil. 



INSECTS ON THE STEMS 



The most likely insect pests are red spider, 

 thrip, scales, and mealy bug. The two 

 latter are easily brushed off with a small 

 brush, but if the stems are frequently 

 syringed with clear water, soap suds, tobacco 

 water, or a solution of fir tree oil, none of 

 these pests will give serious trouble. The 

 red spider will never appear if watering is 

 frequent enough. The fir tree oil pre- 

 vents thrips. 



Cactuses are not helped by rich feeding. 

 The only exceptions to this rule are old 

 plants of night-blooming cereus, and the 

 crab cactus (Epiphyllum), which occasional 

 waterings with weak manure water (about 

 half the strength used for other plants) will 

 benefit. 



IDEAL GROWING CONDITIONS 



The ideal place for cactuses in winter is a 

 rather damp greenhouse, but they will thrive 



