Broadleaf Crops Research Articles

Plutonium contents of broadleaf vegetable crops grown near a nuclear fuel chemical separations facility.

Among agricultural crops, broadleaf vegetables are particularly prone to intercept and retain aerially released contaminants. The plutonium concentration of four broadleaf crops (broccoli, cabbage, lettuce and turnip greens) was determined, when grown in close proximity to a nuclear-fuel chemical-separations facility. Concentrations varied among species, apparently influenced by the crop morphology, with Pu concentrations increasing in the sequence: cabbage less than broccoli less than turnip greens less than lettuce. Washing of the crops significantly reduced the Pu concentration of lettuce, but had no effect on Pu concentration of broccoli and cabbage. The vast majority of Pu found in the crops was due to direct deposition of recently released Pu and resuspension of Pu-bearing soil particles, and was not due to root uptake. Resultant doses from consumption are small relative to the annual background dose.

Effects of Herbicides on Germination and Seedling Development of Three Native Grasses

Two experiments conducted in growth chambers examined influences of 2,4,5-T [(2,4,5-trichiorophenoxy) acetic acid], chiopyraiid (3,6_dichioropicolhtic acid), picioram (4amino-3,5,6-trichloropicoiinic acid), and triclopyr ([3,5,6-trichioro-2-pyridinyi)oxyJacetic acid] on germination and early seedling development of buffalograss [Bucliloc dactyloides (Nutt.) Engelm.], blue grama [Boulelouu grucilis (H.B.K.) Lag. ex Griffiths], and rideoats grama [Boutelow curt@endula (Michx.) Torr.]. Germination and plumule growth were largely unaffected by chlopyralid but were significantly reduced by 2,4,5-T, piclorrm, and triclopyr, especially at rates greater than 1.1 kg/ha. Blue gramr was less affected by herbicides than either buffalograss or sideoats grama. While effects of herbicides on target species have received major attention in the literature, relatively little research has been conducted on herbicidal effects on nontarget desirable species (Scifres and Halifax 1972b). Scifres and Halifax (1972a) observed that picloram acid at 1 mg/ L did not affect germination of buffalograss [Buchloe ducryloides (Nutt.) Engelm.], sideoats grama [Bou~eloua curtipendula (Michx.) Torr.], or switch grass (Panicum virgatum L.), but early seedling growth was affected. Baur (1978) found that applications of pelleted or liquid picloram at rates as high as 3.4 kg/ ha did not affect establishment of ryegrass (Loliumperenne L.) pastures. Conversely, Arnold and Santelmann (1966) found that preemergence applications of picloram at 0.84 kg/ha prevented emergence of blue grama [Bourelouu grucilis (H.B.K.) Laq. ex Griffiths] and sideoats grama from soil. Sideoats grama was injured by picloram at rates up to 2.2 kg/ ha (Bovey et al. 1979). Scifres and Halifax (1972b) indicated that applications of picloram prior to or following range seeding could complicate seedling establishment. Although phenoxy herbicides toxic to broadleaved species are not usually toxic to grasses, several researchers (Brock et al. 1970, Getzendaner et al. 1969, Morton et al. 1967) have noted that grass species absorb herbicides, at least for a short time following foliar application. Lee (1970) observed when established stands of creeping bentgrass (Agrostispalustris Huds., var. Penncross and Seaside), Kentucky bluegrass (Poaprutensis L., var. Newport), perennial ryegrass var. Linn, Italian ryegrass (L&urn multiflorum Authors are research technician and associate professor, Texas Agricultural Experiment Station, P.O. Box 1658, Vernon 76384. The authors wish to express their appreciation to George Warner Seed Co., Hereford, Texas, for their contribution of seed and to Dow Chemical Co., Midland, Mich., for supplying herbicides. This article is being published as technical article TA-18036 from the Texas Agricultural Experiment Station. Manuscript received April 1, 1983. Lam., var. Gulf), tall fescue (Fesruca arundinuceu Schreb., var. Alta), and creeping red fescue (Festuca rubra L., var. Pennlawn) were treated with up to 2.2 kg/ ha of picloram, the germination percentage of seed produced did not differ significantly from check plots. Canode (1974) indicated that September applications of picloram at rates up to 3.4 kg/ ha did not significantly reduce seed germination of Kentucky bluegrass, smooth bromegrass (Bromus inermis Leyss.), orchardgrass (Dactylis glomerata L.), crested wheatgrass[Agropyron deserrorum (Fisch.) ex. Link Schult.], and red fescue. April application of picloram at rates above 1.7 kg/ ha reduced germination of bromegrass and red fescue seed. Bovey and Meyer (I 98 1) found kleingrass and certain grass crop species were more tolerant to broadcast applications of 2,4,5-T, triclopyr, and chlopyralid than broadleaf crops, and triclopyr was usually more phytotoxic than the other herbicides. The objective of this study was to quantify the effects of 4 commercially formulated herbicides, presently considered for brush management, on germination and early growth of 3 major range grasses.

Fluazifop-butyl for selective control of many grass weds in broadleaf crops

Fluazifop-butyl for selective control of many grass weds in broadleaf crops

Response of Monocotyledons to HOE 22870 and HOE 23408

In the greenhouse, postemergence treatments of 1.12 kg/ha of HOE 22870 [4-(4′-chlorophenoxy)-phenoxy-α-propionic-isobutylester] or HOE 23408 methyl 2-[4-(2,4-dichlorophenoxy)phenoxy] propanoate were applied to three perennial weeds (two grasses and one sedge) and to 27 species or varieties of annual grasses (crops and weeds). The perennials were resistant to both compounds, but control of the seedling grasses ranged from 0 to 100%, indicating the potential of controlling certain grass weeds in certain grass crops, as well as in broadleaf crops. Generally, the response of a given species was similar for both compounds. However, on some grasses one compound was considerably more effective than the other. Seven species or varieties of foxtail (Setariaspp.) were treated with various rates of either compound. Differential responses were observed, but it appeared that all the foxtail species or varieties studied should probably be controllable with HOE 23408. All but yellow foxtail [Setaria lutescens(Weigel) Hubb.], should probably be controllable with HOE 22870.

The Host Range of Larvae of the Western Corn Rootworm: Further Studies123

A total of 44 species of grass, 12 species of broadleaf weeds, and 15 species of broadleaf crops were screened in the laboratory as possible hosts of the larvae of the western corn rootworm, Diabrotica virgifera LeConte. The larvae did not survive the 10-day test period on any of the broad lcaf species, but 18 grass species supported larvae for at least 10 days. In subsequent field tests, western corn rootworms were able to complete their immature stages on 13 of these 18 potential hosts, but corn was the most favorable host for larval development as indicated by the number and relative size of the beetles recovered. Viable eggs were obtained from females reared on all hosts except for the single unfertilized female obtained from barley.