18 ORCHARD GREEN-MANURE CROPS 1N CALIFORNIA. 
plants approach maturity the lower portions of the stems become 
dry and wiry, making the turning under difficult. 
Aphids, or plant lice, are very fond of peas and nearly every year 
their attacks occasion considerable damage. In the coast sections or 
those having more humid conditions, the crops also suffer severely 
from the attacks of mildew. Inland, however, there has been but 
little injury from this cause. 
While field peas are in some ways objectionable they also have 
certain qualities that make them serve special purposes. Their 
ability to stand late fall planting and still produce a fair winter 
growth makes them especially valuable for such use when for any 
Fic. 4.—View in an orange orchard in southern California, showing Canada field peas grown as a green- 
manurecrop. — 
reason an earlier planting of other crops has not been accomplished, 
but if sown late only a very ordinary crop can be expected. While 
peas may be planted from the middle of September to the end of 
November, in southern California the best results are secured from 
September plantings. In the northern part of the State the middle 
of October is better for planting because the winter rains prevent the 
crop from being turned under until later in the winter. When planted 
early, peas in the north are also likely to suffer more severely from 
winter frosts. 
Seventy pounds of seed per acre is the usual rate of seeding. 
This in some cases gives a very good crop but a thin stand, and 
therefore a light yield has been very noticeable in all orchard 
190 
