in living host cells. Its vegetative phase consists of a multinucleate mass of protoplasm lacking a cell wall (plasmodium or slime mold). Although the organism primarily attacks members of the Cruciferae, the intensity of disease caused on different crops...
(see "Host Range") varies. The organism also exists as many specialized forms or races, the variation in plant resistance and ability to survive in different areas being explained thereby. Symptoms Clubroot may develop extensively on plant roots before...

, including insecticides that may be approved for organic production: veg-guidelines.cce.cornell.edu. 5 Boivin, G. and D. L. Benoit. 1987. Predicting onion maggot (Diptera: Anthomyiidae) flights in southwestern Québec using degree-days and common weeds...
entry points for bacterial pathogens that can cause bulbs to rot. Feeding by third-generation larvae on mature onion bulbs can result in an unmarketable product (Fig. 4). Even after onions are undercut, windrowed, and left to dry in the field, bulbs may...

) , Colletotrichum can cause severe rotting of below-ground plant parts and early plant decline leading to discolored tubers and reduce~ yields. The same black dot organism causes anthracnose or npe-fru1t disease of tomato, and can occur on other solanaceous crops...
, the organism does not penetrate intact tuber skin, but can grow and sporulate on damaged tissue. This limited growth, however, does not appear to provide entry sites for secondary fungal or bacterial invaders in stored tubers. In a three-month greenhouse test...

rot develops slowly and may not be severe until quite late into the storage period. This decay may allow the entry of secondary organisms such as Fusarium fungi and soft rot bacteria. �CONTROL The following measures will help prevent the occurrence...
. Surface tubers infected by conidia washed from leaves. ~,'~'~:~~"~:,~~:~~,-'".~"~~~~"'~",~",~~~ ~~~~~' ~~"~ "Target" spots Early Blight Disease Cycle Adapted in part from North Dakota State University Extension Bulletin 26, 1976, 'Potato Production...

-green, yellowish to brownish areas of irregular size and shape (oval tocylindrical) on infected leaves or seed stalks (Fig. 1). These areas may consist of alternating yellow and green layers of tissue. The causal organism of DM produces fruiting bodies and spores...
the night and morning hours. Secondary Spread The mycelium of DM in leaves of infected onion plants in commercial bulb production fields produces a new crop of spores called conidia in cycles of approximately 11-15 days. As the upper portions of a leaf...

seeking hibernation sites in the fall may become a nuisance on the walls and at doorways and windows where they congregate. Control Numerous natural control organisms exist in the field. Both parasites and predators are useful. A fungus Beauveria bassiana...
for maximum potato production. In many areas of the Northeast the Colorado potato beetle has become resistant to most pesticides. Control is further complicated by the ability of the species to produce thousands of new eggs per acre. Consult your local...

colonize and produce spores (conidia) on almost any plant debris. It overwinters in strawberry plantings on decayed foliage and fruit from the previous season . Increasing temperatures and moisture in the spring promotes fungal growth and production...
in organic debris spring wetting initiates fungus growth and sporulation con7direct infection of mature fruit are covered with fuzzy conidial masses Botrytis Fruit Rot Disease Cycle fungus infects senescing blossom parts infection spreads from calyx end...

was attributed to a physiological disorder; evidence of other workers in the United States supports this conclusion. Fungal organisms such as Botrytis, Alternaria, and Rhizoctonia may cause spotting and speckling of the outer leaves of cabbage heads...
and production fields. This should be coupled with early aphid control on the crop and bordering areas. Quantity discount available. Cooperative Extension, New York State College of Agriculture and Life Sciences, New York State College of Human Ecology, and New...

activities, and may be present in tobacco products. The virus is not spread by insects commonly occurring in the greenhouse or field. The symptoms in tomato vary greatly in intensity depending upon the variety, virus strain, time of infection, light intensity...
by this mycoplasmalike organism (fig. 8), rendering the plant incapable of setting normal fruit. Leafhoppers are generally not difficult to control in temperate climates; thus, vector control should reduce the incidence of this disease. Quantity discount available...

in rejection by the processors and, thus, a significant loss of product. PEST MONITORING European corn borer moth populations can be moni- tored by using blacklight traps, pheromone (sex attractant) traps, or by direct observations of moths in the field...
for the number and developmental stage of egg masses and/or the percentage of feeding signs. It is not practical to sample for egg masses or for borer infestations in snap beans. CONTROL Parasites, predators, and disease organisms can play a significant role...