Fungous Diskasi^s of Couorado Crop Puants 31 
LETTUCE. 
Lfttucf Drop. —The first indication of the disease is a sickly 
plant. Later the outer leaves wilt, one after the other, and fall flat 
upon the ground. Finally, water-soaked areas are produced over 
the stem, and the whole plant falls over and rots away. Such plants 
show a cottony growth on the under side of affected leaves. In the 
last stages of the disease, many small black bodies may be formed 
upon the affected portions. 
Control .— (I) Remove and burn all diseased plants as soon as 
they appear. 
(2) Spray the place where the infected plants stood, either 
with Bordeaux mixture, .4-5-50 formula, or with bluestone dis¬ 
solved in water at the rate of one pound to seven gallons of water, 
or with weak formalin. 
(3) Guard against introduction of the trouble in refuse or 
compost which may contain diseased lettuce plants. 
(4) Rjotation. Do not follow lettuce with celery, or celery 
with lettuce, as both crops are subject to the disease. 
(5) Set out healthy plants only. 
(6) Soil steaming or sterilization is practicable for lettuce 
grown under glass. 
ONION. 
Buight or Mildew. —In a few of the truck growing regions 
of the state, this disease has been rather serious. It makes its ap¬ 
pearance the latter part of June or first part of July. Damp weather 
or excessive irrigation favors its development. It is possible to rec¬ 
ognize the disease in its very young stages. Early in the morning, 
when there is moisture on the leaves, infected leaves have a peculiar, 
furry, violet tinge. Later on, they become covered with a white 
mildew-like growth, and finally collapse. As a result of the leaf 
infection, the onion bulbs do not reach their proper size. 
Control .— (i) In case of serious outbreak of disease, spray 
with 4-5-50 Bordeaux mixture. Apply this from time to time until 
disease is checked. 
(2) The disease is carried over the winter on dead onion 
leaves. Care should be taken to rake and burn all the tops. 
(3) In case the disease has been serious for several successive 
years, it may be well to practice crop rotation, not going back to 
onions until three or more years. 
PEA. 
Powdery Mildew. —This disease is prevalent in the state on 
both garden and field peas. It is readily recognized by the white 
cobwebby growth on both surfaces of the leaves. Moist weather, 
