| synthesis of new aliphatic and aromatic phytotoxic derivatives of 2alpha,4alpha-dimethyl-8-oxabicyclo[3.2.1]oct-6-en-3-one. | several new compounds with potential herbicidal activity were synthesized from 2alpha,4alpha-dimethyl-6,7-exo-isopropylidenedioxy-8-oxabicyclo[3.2.1]octan-3-one (4). seven aromatic alcohols were prepared by reaction of (4) with aryllithium reagents, where the aryl groups were 4-ethoxyphenyl (5, 70% yield), 4-ethylphenyl (6, 82% yield), 4-butylphenyl (7, 78% yield), 4-tert-butylphenyl (8, 81% yield), 2,4-dimethoxyphenyl (9, 75% yield), 2-ethylphenyl (10, 12% yield) and para-(4-bromophenoxy)phenyl ... | 2003 | 12974357 |
| population dynamics of plant nematodes in cultivated soil: effect of summer cover crops in old agricultural land. | in a 6-year cover crop sequence study, nematode population densities varied with different cover crops. millet favored rapid increase of belonolaimus longicaudatus and supported relatively large numbers of pratylenchus brachyurus. beggarweed and 'coastal' bermudagrass favored rapid increase of b. iongicaudatus and to a lesser extent p. brachyurus and trichodorus christiei. hairy indigo and crotalaria supported relatively large numbers of p. brachyurus but suppressed b. longicaudatus. hairy indig ... | 1970 | 19322288 |
| population dynamics of plant nematodes in cultivated soil: effect of summer cover crops in newly cleared land. | five nematode species were studied for ability to develop on seven summer cover crops in rotation with tomato transplants grown every third year. increase of tylenchorhynchus claytoni, trichodorus christiei, pratylenchus brachyurus, helicotylenchus dihystera, and xiphinema americanum in newly cleared soil varied with different cover crops. no substantial nematode population increases occurred until the third summer of crop growth. all species except x. americanum and h. dihystera developed best ... | 1970 | 19322300 |
| epiphytic survival of pseudomonas viridiflava on tomato and selected weed species. | a rifampicin-nalidixic acid mutant of pseudomonas viridiflava (pv) was studied in the field and greenhouse with respect to its epiphytic survival on the roots and foliage of a susceptible (fm 6203) and resistant (ontario 7710) tomato cultivar and 16 weed species. in the field, populations varied between years, which was attributed to differences in environmental conditions. hot, dry conditions caused rapid decline or elimination of populations. some hosts were more conducive than others in promo ... | 1993 | 24189988 |
| flight activity ofheliothis virescens (f.) females (lepidoptera: noctuidae) with reference to host-plant volatiles. | heliothis virescens (f.) females responded positively via upwind flight in laboratory assays to volatiles emitted from methylńe chloride washes of fresh whole leaves of host plants including cotton, tobacco, and a weed species,desmodium tortuosum (swartz) de candolle. except ford. tortuosum, the response increased positively with dose; the steepest slope occurred with an extract of cotton squares (flower buds). almost all of the moths that landed on the extract dispenser also oviposited. moths s ... | 1991 | 24258724 |
| preferences of matedheliothis virescens andh. subflexa females for host and nonhost volatiles in a flight tunnel. | in flight-tunnel bioassays, mated femaleheliothis subflexa (gn.) moths demonstrated in dual-choice tests a significant preference for volatiles from an extract of their only known host,physalis spp. (groundcherry). however,h. virescens (f.), a polyphagous species, responded positively by anemotaxis to extracts from susceptible tobacco, cotton,desmodium tortuosum (host plants), and groundcherry, a nonhost.h. virescens females did not fly to volatiles emanating from an extract of a resistant tobac ... | 1990 | 24263262 |
| ovipositional response of threeheliothis species (lepidoptera: noctuidae) to allelochemicals from cultivated and wild host plants. | the role of plant allelochemicals on the oviposition behavior ofheliothis virescens (f.),h. subflexa (guenee), andh. zea (boddie) was investigated in the laboratory using a "choice" bioassay system. fresh young leaves of tobacco,desmodium tortuosum (swartz) de candolle, groundcherry (physalis angulata l.), and cotton (gossypium hirsutum l.) squares (flower buds) were washed in methylene chloride or methanol, concentrated to 1 g equivalent of washed material, and applied to a cloth oviposition su ... | 1990 | 24263986 |