Low-energy Grubbing with Special Blade to Control Algerita

Abstract

Algerita (Berberis trifoliolata Moric) infestations on low stony hill range sites in the Edwards Plateau vegetational area of Texas are a problem following primary brush control. Infestations appear well suited to control by low-energy grubbing. A feasibility study indicated the method was economical but plant kill was erratic. Sprouting of lateral roots near the periphery of the grubbed hole accounted for 56% of the regrowth while 13% was attributed to crown tissue attached to taproots. No sprouts originated directly from taproots. Remaining regrowth resulted from problems with blade penetration in the soil. To prevent sprouting, severing the taproot below the crown and uprooting of all lateral roots under the entire plant canopy to a depth of 10 to 15 cm was necessary. Grubber blade modification included an increase in width to 180 cm and an addition of small fins welded on top of the blade to increase plant uprooting. Grubbing with the modified blade resulted in a plant kill of 93% +/- 3.5 (x +/- S.D.) when tested in an algerita infestation of 42 to 195 plants/ha ranging in height from 1.0 to 1.5 m. The grubber averaged 2.13 ha/hr in a 110 plants/ha infestation and cost of $16.43/ha. The ha/hr grubbing rate (Y) plotted against trees/ha densities (X) followed the prediction equation log Y = 1.93 - 0.83 log X with a significant (P<0.01) correlation coefficient of r = 0.91. Low-energy grubbing using the modified grubbing blade is an effective and economical method of controlling algerita.