Effect ofDactylaria higginsiion interference ofCyperus rotunduswithL. esculentum

Abstract

Greenhouse experiments were conducted to evaluate the effect of the fungusDactylaria higginsiion the interference ofCyperus rotundus(purple nutsedge) withLycopersicon esculentum(tomato ‘Agroset').Cyperus rotundusplants established from tubers were planted at initial densities equivalent to 40, 80, 160, and 320 tubers m−2withL. esculentumin 35-cm-diam pots.Cyperus rotundusplants were inoculated by spraying with a spore suspension ofD. higginsiicontaining 0.5% Metamucil as a carrier. The treatments were Metamucil only, 104conidia ml−1+ Metamucil, or 106conidia ml−1+ Metamucil. In the absence ofD. higginsii, C. rotundusat densities of 80, 160, and 320 tubers m−2reducedL. esculentumyield by 14, 68, and 70%, respectively. In contrast, yield ofL. esculentumtreated withD. higginsiiat 106conidia ml−1was equal to that in the weed-free control. The rate of disease increase (rG) was higher in treatments with 106conidia ml−1(rG= 0.126 to 0.136) compared to 104conidia ml−1(rG= 0.046 to 0.050). At 106conidia ml−1D. higginsiireduced the interference fromC. rotundus, controlledC. rotundusbetter, and increasedL. esculentumyield compared to the weedy checks.