Chloropicrin Enhancement of Metam-sodium as an Alternative to Methyl Bromide for Mulched Tomato

Abstract

Studies were conducted during two seasons with metam-Na combined with chloropicrin (pic) + pebulate as an alternative to methyl bromide-pic (MBr-pic) fumigation for polyethylene mulched tomato (Lycopersicon esculentum Mill.). In fall 1997 on a Millhopper fine sand, marketable yields with MBr-pic,1,3- dichloropropene plus 35% pic (1,3-D + 35% pic) and metam-Na plus pic were significantly higher than with the check. Fruit yield with metam-Na alone was similar to that with the untreated check. Counts of purple and yellow nutsedge (Cyperus rotundus L. and Cyperus esculentus L.) that grew through the mulch were lower with MBr-pic and all treatments with pebulate than with the check. Metam-Na treatments, alone and with pic, (without pebulate) resulted in nutsedge counts statistically similar to that with no fumigant treatment. Root-knot nematode (Meloidogyne incognita (Kofoid & White) Chitwood) gall ratings after harvest were high on
tomato grown without fumigants, low with Mbr-pic, and inter mediate with all other treatments. In spring 1998, on an additional site of Millhopper fine sand, fruit yields were highest with MBr-pic, 1,3-D + 35% pic plus pebulate, and were significantly lower with no fumigant treatment. Yields were similar to that with MBr-pic with metam-Na alone, and pic plus pebulate. However, yields with some metam-Na treatments were similar to that with the check. Fruit yields with metam-Na, with and without pic, were not significantly different. Root-knot nematode gall ratings were lowest with MBr-pic and with 1,3-D + 35% pic plus pebulate, and significantly higher with no fumigant treatment. Root- knot gall ratings were significantly higher with all metam-Na treatments than with the above Studies were conducted during two seasons with
metam-Na combined with chloropicrin (pic) + pebulate as an alternative to methyl bromide-pic (MBr-pic) fumigation for polyethylene mulched tomato (Lycopersicon esculentum Mill.). In fall 1997 on a Millhopper fine sand, marketable yields with MBr-pic,1,3- dichloropropene plus 35% pic (1,3-D + 35% pic) and metam-Na plus pic were significantly higher than with the check. Fruit yield with metam-Na alone was similar to that with the untreated check. Counts of purple and yellow nutsedge (Cyperus rotundus L. and Cyperus esculentus L.) that grew through the mulch were lower with MBr-pic and all treatments with pebulate than with the check. Metam-Na treatments, alone and with pic, (without pebulate) resulted in nutsedge counts statistically similar to that with no fumigant treatment. Root-knot nematode (Meloidogyne incognita (Kofoid & White) Chitwood) gall ratings after harvest were high on tomato grown without fumigants, low with Mbr-pic, and intermediate with all other treatments. In spring 1998, on an additional site of Millhopper fine sand, fruit yields were highest with MBr-pic, 1,3-D + 35% pic plus pebulate, and were significantly lower with no fumigant treatment. Yields were similar to that with MBr-pic with metam-Na alone, and pic plus pebulate.
However, yields with some metam-Na treatments were similar to that with the check. Fruit yields with metam-Na, with and without pic, were not significantly different. Root-knot nematode gall ratings were lowest with MBr-pic and with 1,3-D + 35% pic plus pebulate, and significantly higher with no fumigant treatment. Root- knot gall ratings were significantly higher with all metam-Na treatments than with the aboveStudies were conducted during two seasons with metam-Na combined with chloropicrin (pic) + pebulate as an alternative to methyl bromide-pic (MBr-pic) fumigation for polyethylene mulched tomato (Lycopersicon esculentum Mill.). In fall 1997 on a Millhopper fine sand, marketable yields with MBr-pic,1,3- dichloropropene plus 35% pic (1,3-D + 35% pic) and metam-Na plus pic were significantly higher than with the check. Fruit yield with metam-Na alone was similar to that with the untreated check. Counts of purple and yellow nutsedge (Cyperus rotundus L. and Cyperus esculentus L.) that grew through the mulch were lower with MBr-pic and all treatments with pebulate than with the check. Metam-Na treatments, alone and with pic, (without pebulate) resulted in nutsedge counts statistically similar to that with no fumigant treatment. Root-knot nematode (Meloidogyne incognita (Kofoid & White) Chitwood) gall ratings after harvest were high on tomato grown without fumigants, low with Mbr-pic, and inter mediate with all other treatments. In spring 1998, on an addi tional site of Millhopper fine sand, fruit yields were highest with MBr-pic, 1,3-D + 35% pic plus pebulate, and were signifi cantly lower with no fumigant treatment. Yields were similar to that with MBr-pic with metam-Na alone, and pic plus pebulate. However, yields with some metam-Na treatments were similar to that with the check. Fruit yields with metam-Na, with and without pic, were not significantly different. Root-knot nema tode gall ratings were lowest with MBr-pic and with 1,3-D + 35% pic plus pebulate, and significantly higher with no fumigant treatment. Root- knot gall ratings were significantly higher with all metam-Na treatments than with the aboveStudies were conducted during two seasons with metam-Na combined with chloropicrin (pic) + pebulate as an alternative to methyl bromide-pic (MBr-pic) fumigation for polyethylene mulched tomato (Lycopersicon esculentum Mill.). In fall 1997 on a Millhopper fine sand, marketable yields with MBr-pic,1,3- dichloropropene plus 35% pic (1,3-D + 35% pic) and metam-Na plus pic were significantly higher than with the check. Fruit yield with metam-Na alone was similar to that with the untreated check. Counts of purple and yellow nutsedge (Cyperus rotundus L. and Cyperus esculentus L.) that grew through the mulch were lower with MBr-pic and all treatments with pebulate than with the check. Metam-Na treatments, alone and with pic, (without pebulate) resulted in nutsedge counts statistically similar to that with no fumigant treatment. Root-knot nematode (Meloidogyne incognita (Kofoid & White) Chitwood) gall ratings after harvest were high on
tomato grown without fumigants, low with Mbr-pic, and inter
mediate with all other treatments. In spring 1998, on an addi tional site of Millhopper fine sand, fruit yields were highest with MBr-pic, 1,3-D + 35% pic plus pebulate, and were significantly lower with no fumigant treatment. Yields were similar to that with MBr-pic with metam-Na alone, and pic plus pebulate. However, yields with some metam-Na treatments were similar to that with the check. Fruit yields with metam-Na, with and without pic, were not significantly different. Root-knot nematode gall ratings were lowest with MBr-pic and with 1,3-D + 35% pic plus pebulate, and significantly higher with no fumigant treatment. Root- knot gall ratings were significantly higher with all metam-Na treatments than with the above treatments, and were similar to ratings with no fumigant treatment. Nutsedge control was excellent with MBr-pic and with 1,3-D + 35% pic plus pebulate and was poorer and not consistent with the addition of pic and pebulate with metam- Na. At
the Green Acres site on an Arredondo fine sand, southern blight caused by Sclerotium rolfsii resulted in death of over 40% of the plants in untreated plots. Loss was significantly less with all fumigant treatments, however, addition of pic at various rates with metam-Na did not reduce losses to the disease. Thus, the addition of pic to metam-Na generally did not significantly increase the performance of metam-Na in weed control, pest control, and enhanced fruit production as compared to treatments with metam-Na without pic.