102 Butterflies and Moths [CH. 
Other Caterpillars. 
There are numerous other caterpillars (i.e. the larvae 
of butterflies or moths) which cause damage to our 
crops and especially to fruit trees. These may be 
distinguished from other larvae by the key on p. 92. 
Some of them are kept down by grease-banding the 
trees which prevents the wingless females from reaching 
the shoots. In other cases the trees are sprayed with 
a poisonous substance such as lead arsenate, so that 
when the caterpillars feed, they are poisoned. In 
addition to the caterpillars of the large cabbage 
butterfly we may find on cabbages those of the small 
cabbage butterfly eating holes in the leaves, and also 
the green or brown caterpillars of the cabbage moth 
(Mamestra brassicae) which eat into the hearts of the 
cabbages, leaving a lot of excrement behind them. As 
the small cabbage butterfly lays its eggs singly it is 
difficult to control. 
The cabbage moth lays its eggs in groups and these 
should be looked for and destroyed in July and early 
August. 
The small caterpillars of the diamond-back moth 
(Plutella maculipennis) may check or even destroy 
crops of turnips and swedes by feeding on their leaves. 
In this case the plants should be immediately brushed 
with large twigs attached to a scuffle. 
