1922.] 



The Eiiododendron Bug. 



557 



considerable and the old leaves are crowded with bugs, the latter 

 seem to spread more readily to the new leaves and then these 

 also show signs of injury. The eggs are laid both on the old 

 leaves and on those of the current season, not exclusively on the 

 latter as has been suggested by some writers. 



The spread of the insects from one pnrt of the country to 

 another is almost certainly due to the distribution of infested 

 plants, but in gardens the bugs presumably move from plant to 

 plant even though they seldom seem to use their wings. Too 

 much weight, however, must not be placed on the lack of records 

 of the bugs being seen on the wing, for many usually sluggish 

 insects fly freely under some special weather conditions which 

 perhaps occur on one or two days only during the year. 



Methods of Control.— 1. S^raying.—ln U.S.A. rhododendron 

 bugs are killed by spraying them with such an insecticide as soap 

 and water. The chief difficulty consists in wetting thoroughly 

 the undersides of the leaves, which is absolutely essential if 

 success is to be obtained. In the case of small plants and even 

 large bushes, the difficulty can be overcome by the exercise of 

 sufficient care on the part of those spraying, but it is almost in- 

 superable where dense thick shrubberies are concerned unless 

 they are of such value as to justify considerable expense. In 

 spraying rhododendrons it is worth noting that the leaves are 

 easily injured and the work should be done on dull days or in 

 the evening. 



A simple soap wash may be made by dissolving 1 lb. of good 

 soft soap in 10 gallons of water. A nicotine wash is more effec- 

 tive and its use is certainly justified in the case of valuable 

 plants or where an attempt is being made to eradicate the pest 

 as opposed to preventing serious injury. It is made by adding 

 1 fluid oz. of 95-98 per cent, nicotine to each 10 gallons of the 

 above soap wash. If soft water is available the soap may be 

 reduced to J lb. to 10 gallons. 



2. Strij)ping and Hand-Picking. — As the eggs are laid on the 

 leaves it is clear that if the latter are all removed and burnt 

 during winter the insects should be destroyed. It is not yet 

 known how far this is a practical treatment but it may be men- 

 tioned that certain foreign countries appear to be adopting it in 

 the case of rhododendrons for export. Hand-picking in sumuier 

 is quite effective in the case of a few rhododendrons or at the 

 first appearance of the bug in a previously uninfested garden. 

 The signs of injury are so characteristic and obvious that it is 

 not a difficult matter to remove and destroy infested leaves wit I) 

 the insects upon them. 



