Mole Cricket Control in Shade Tobacco Plant Beds

Abstract

The Southern mole cricket, Scapteriscus acletus Rehn and Hebard, and the changa, S. vicinus Scudder, have long been recognized as pests in tobacco plant beds in the Quincy, Florida, area, with the Southern mole cricket being the more prevalent species. Chamberlin and Madden (1942) observed that mole crickets were increasing in importance as plant bed pests, causing little damage by actual feeding on plants, but some injury from burrowing in the soil layer subjacent to the soil surface. Tobacco seedlings in the soil layer superjacent to the burrows often died from lack of moisture caused by the disruption of capillarity existing between the water table and the soil surface. Not only did the burrowing cause death of plants, but it caused the soil to become so desiccated that seed failed to germinate. Damage by these pests was counteracted by use of overhead irrigation to return the soil to its original position or by compacting the soil into position by pressing the raised burrows with the foot or some improvised tamping tool. These methods were laborious and unsatisfactory; therefore, insecticidal control measures were indicated. The first economic mole cricket control developed for shade tobacco consisted of a bait containing a stomach poison of either calcium arsenate or paris green (Chamberlin and Madden, 1942). Although this bait gave satisfactory control at that time, its effectiveness as a stomach poison depended to a large extent upon the actual feeding of the mole crickets upon the bait. Later, sodium fluosilicate proved to be satisfactory as a stomach poison in a bait (Wisecup and Hayslip, 1953). Control with contact poisons became a reality with the advent of organic chlorinated-hydrocarbon and phosphate insecticides in the 1940's. Kelsheimer (1950), working with vegetables and other crop plants, found that chlordane wettable powder or emulsifiable concentrate incorporated into the soil prior to seeding of plant beds gave excellent protection from mole crickets. However, the bait method persisted because it was economical and had the prestige of established grower usage (Reid and Cuthbert, 1955; Kuitert and Tissot, 1956; and Guthrie, et al., 1958). Although baits continued to be recommended, the toxic ingredient was changed to chlordane, which also acts as a contact poison if, or when, enough bait is broadcast onto a plant bed. Guthrie et al. (1958) recommended using a drench containing parathion for fluecured tobacco plant beds. In shade-tobacco plant beds, control of all insects is based upon prevention of damage to insure an adequate supply of healthy insect-free plants of uniform size for transplanting in the field. The prevention of all insect damage is not always obtained, as is often the case in a control program of this type, but shade tobacco growers continually strive for that degree of perfection in order to glean the highest monetary return from their crop. Observations prior to 1958 indicated that the critical mole cricket control period in plant beds was approximately 40 to 50 days from seeding, de-