STATE HORTICULTURAL SOCIETY. 131 
Dr. Ward of New Jersey, a number of years since commenced the plan of 
cultivating his pear orchard early in. the season, and covering the whole 
surface with marsh-hay in July. His orchard has since borne fine crops and 
been very nearly exempt from blight. His neighbors, following his example, 
have had equal success, while the skeptical ones, having other theories in 
regard to the cause of the disease and keeping on in the old way, have lost 
their trees. Thomas Meehan, while believing in and teaching that blight is 
caused by fungus development in the tissues, yet, for many years has con- 
tinued to point out the fact that wherever he has gone, east or west, apples, 
pears, peaches, raspberries, and plums, that ‘‘ have somehow got out of the: 
ruts of what is sarcastically called cultivation, and into some happy spot. 
where they can push their roots on a nice, cool, shaded, and regularly 
humid surface,” are uniformly healthy and productive. We can only sum- 
marize our prairie experience by saying: 
1. Apple trees blight least on light-colored soils, in elevated, airy posi- 
tions. 
2. We find a wide range of varieties to fatally blight on dark-colored, 
exposed soils, in sheltered positions. 
3. We find the disease confined to few varieties, and to assume less seri- 
ous form, in orchards with surface shaded in August by a succulent sevond- . 
growth of clover. 
4. We rarely find a blighted twig in an orchard or nursery with its sur- 
face covered the preceding season by a thick growth of buckwheat. 
5. We note little blight in orchards where a coating of weeds and rubbish 
are lightly turned under in June, followed by a growth of succulent weeds in 
July and August. 
6. Orchard trees kept whitewashed on the trunks and main limbs during 
the iatter part of the season’s growth rarely show traces of blight. 
In all these cases we can readily trace the cause of blight to unnatural 
heating of the internal structure of the trees during the season when the 
newly-formed wood and inner bark are maturing. Earlier in the season 
the forming cell-structure is loaded with fluids and seems little affected by 
excess of heat. We have neither the time or inclination to speculate on the 
exact manner in which an internal temperature of 95 to 98 degrees works 
injury to the maturing cell-structure of the English Golden Russet or 
Transcendent Crab, while an internal temperature of 120 degrees may not 
injure an orange or a fig at the Cape of Good Hope. We fully believe the 
damage is done at the time and in the way indicated. If the damage is 
specially severe, the visible results may appear in patches of discolored 
bark the same season. But almost as a rule the sap ascends in the wood of 
the older growth, as it will do in rabbit-girdled trees, and the trees make 
about their usual extension of apparently healthy growth. Earlier or later 
in June, according to the season, the time arrives for new wood deposit 
over the injured cell-structure of the previous August, when the blight 
appears just where we may expect it, in the growing points immediately in 
communication with the forming cambium layer. 
We do not expect at once a large number of believers in this simple 
theory of blight. We only ask that it be carefully investigated. But appar- 
ent exceptions must be carefully studied. Trees standing near buildings, 
surfaces of exposed soils, or with other conditions where an internal heat 
