Cr 
mens, but overfeeding causes perhaps 
more damage and shortens their lives more 
than any other factor. The quick acting 
fertilizers such as fish-meal and_fish- 
emulsion are of organic nature and can 
hardly do damage unless used in excessive 
quantities. The first sign of overfeeding 
is a rich bluish-green color of the leaves 
which curl under. The plants will produce 
distorted flowers smaller in size, but grad- 
ually as the nitrogen in the soil diminishes, 
they will come out of it and perform nor- 
mally. If chemical nitrogen is used in such 
form as nitrate of soda, sulphate of am- 
monia or nitrate of potash, the plants 
simply burn up if overfed. The growth 
will be stunted with small flowers or none, 
and upon maturing the tubers, you will 
find them completely petrified. The ideal 
feeding is to keep the plants always slightly 
hungry by giving them light doses of 
liquid fish-meal or any other commercial 
fertilizer recommended for tuberous be- 
gonias and religiously following the direc- 
tions prescribed on the containers. If 
foliage is a blue-green withhold feeding as 
they are receiving too much nitrogen. Start 
feeding again when the foliage is a soft 
green color. Very pale green foliage is a 
sign of a deficiency of nitrogen and re- 
quires increased feeding. This is a simple 
rule which anyone can see at the first 
glance at the plants. We get the finest 
flowers when plants are underfed and the 
foliage is just deep green. 
Rotting of plants. 
The tissue of begonia plants is quite 
sensitive to any decaying material which 
they contact. If young plants are set out 
in a soil heavily enriched with manure 
and the decaying parts of the manure come 
in contact with the stem, the plant will 
often rot off at the base. This happens 
more in warmer regions especially with 
high humidity and seldom appears under 
cool conditions prevailing along the Pa- 
cific Coast. A little clean soil or sharp 
sand placed around the stem when plant- 
ing seedlings will prevent the rotting off to 
a great extent. When flowering, the plants 
should be kept clean of all the debris of 
the the old flowers and flower stems. 
Flowers should be removed leaving all of 
the flower stem or if cut, as much of the 
stem as possible, as the open wound im- 
mediately starts molding. If a stem is 
left long enough, it will mature and fall off 
from the main stem before the mold can 
reach its entire length. If cut too short, the 
mold will infect the main stem and if not 
checked, will decay the whole plant even- 
tually. Old petals falling in the crotch 
of the leaves may start mold in an area 
which could be scraped clean with a knife, 
dried with a cloth, and dusted over with 
zerlate so it can heal. If the main stem is 
badly molded, it can be cut off below the 
infected part or even completely off if 
necessary. The plant should be kept 
13 
slightly drier as it will send new shoots 
out as a rule trying to recover its health. 
In this way tubers can be saved and al- 
though weakened, they may perform well 
again the following year. If stem rot is not 
checked, it will go all the way down into 
the tuber and destroy it completely. 
Diseases and insects. 
Begonias are comparatively free of ills or 
at least they were until a few years ago. 
The only serious infection in the past was 
cyclamen mite which was rare rather and 
confined usually to greenhouses where 
many other plants were grown. The first 
sign of it is rusty brown streaks on the 
foliage and stems, the buds turning brown 
in the very young stage and falling off. 
An effective control can be had by spray- 
ing with various insecticides recommended 
for red spider and mites. 
Bacteria leaf-spot appeared several years 
ago and attacks the plants chiefly in the 
greenhouses where there is high humidity 
and not enough aeration. It is most dam- 
aging to the young seedlings in their ger- 
mination stage, and we have been con- 
trolling it with a weak solution of Greenol, 
spraying every five days until the plants 
reach the size for outdoor planting. It 
seldom attacks plants when they are larger 
and hardly ever if they are grown outdoors. 
The latest and perhaps the most serious 
enemy is a new variety of mildew reported 
for the first time in 1951 in isolated areas. 
Dusting with sulphur will act as a pre- 
ventive before any signs of the disease are 
shown. However, this does not add to 
the appearance of the plants, and once the 
disease is established, it will not cure it. 
Chemical sprays such as Ortho-rix will con- 
trol the mildew effectively, but no suffi- 
cient experiments have been done yet as to 
find an ideal material which would control 
the mildew and not burn the flowers. Well 
grown plants will resist disease to a great 
extent. Keeping the foliage dry especially 
at night also prevents the spread of any 
fungus disease. 
Strawberry-weavil is wide spread par- 
ticularly in the north, and the damage to 
the begonias is caused by the larvae of the 
brachyrhinus beetle during summer 
months. The beetles emerge from their 
dormant stage in early May and June lay- 
ing their eggs all summer long. ‘The eggs, 
which are deposited around the stem of 
the plant, hatch rapidly, living in their 
first and second stage on decaying material 
such as leafmold and manure. It is in their 
third, fourth, and fifth stage as the larvae 
gets larger that it burrows into the tuber, 
tunneling back and forth until the bulb is 
completely destroyed. The only effective 
control is feeding with a mixture of three 
percent calcium arsenate in bran or apple 
bait spread among the plants during May 
and. June when the beetles feed and before 
the egg laying period begins. 
