The two most important factors in this approach involve timing and completeness
of kill. To be effective the weeds must be controlled when no crops are in the
area. Once the virus is in the crop no amount of weed control will prove effec-
tive. The degree of kill must be high. Simply destroying the top growth of the
nightshade is not enough. The virus is in the roots of the nightshade and re-
growth will be just as infectious as before. The treated area must include not
only ditchbanks but weed and volunteer crop plants in the field itself. One
thorough treatment during the summer should be adequate. Ideally this treatment
should be timed to be as near planting time as possible. Late July and early
August are recommended.

 The biggest drawback to the weed control approach is that it will often
involve cooperation among several growers. Having an abandoned field next to
a pepper field can pretty well nullify the efforts of a farmer on his own farm.
The same thing is true to a lesser extent if the farm next door is in operation
but there has not !ez en ny. ditchbank weed control. This is particularly true
during the Spring when large numbers of winged aphids are present.

 *7. Use nonsusceptible barrier crops around your field -- If a good weed
control program is in effect there is merit in protecting a crop on the outside
of the field with a nonsusceptible crop of from 50-100 feet in width. For virus
Y such crops as beans, corn, cucumber, eggplant, and squash could be used. Low
crops are as good as tall ones. The reasons that a barrier crop works are three-
fold. First, it actually means there will be a greater distance between diseased
weeds and the susceptible crop. Second, aphids fly short distances and will feed
on the barrier crop plants for a long enough time so that most of them lose virus
before getting to the susceptible crop. Third, aphids lose virus faster while
feeding than while flying.

 The principal drawback to this scheme is that many farmers only grow one
crop and cannot easily set up their plantings to utilize a barrier. It should
be emphasized that a barrier crop will not entirely prevent virus-laden aphids
from entering the crop. It will ordinarily delay by several weeks the time it
takes for virus to get into the crop. This can mean a great deal in the effect
on the yield.

 Spraying parathion on the barrier crop is worthwhile. The sprays should be
applied on a 4-5 day schedule.

 *8. Avoid planting spring crops next to diseased fall crops. -- A sure way
to get into trouble is to plant a late tomato or pepper crop next to a badly
infected acreage of tomatoes or peppers. If at all possible destroy the old
pla-ning before putting in the young one. With a good weed control program
mot; plantings made up to November 1 should escape serious virus Y damage.
Beyond that time the situation can change drastically.

 *9. Grow the healthiest crop possible insofar as other diseases are con-
cerned -- Since the greatest loss to virus Y infection is correlated with early
infection it stands to reason that growing a vigorous crop is worthwhile. This
is particularly true insofar as the bacterial spot disease is concerned. Plants
that are badly stunted becease of poor bacterial spot control will suffer more
from virus infection than healthy, rapidly growing ones. These plants are not
more susceptible to the virus but are unable to withstand the ravages of the
disease the way healthy plants can.