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The efficacy of esfenvalerate (84 g litre-1 EC; Asana XL) at 7.0 g AI ha-1 on broccoli was tested against the flea beetle, Phyllotreta cruciferae Goeze (Chrysomelidae: Coleoptera) and the imported cabbage worm, Pieris rapae L (Pieridae: Lepidoptera) under field conditions. Insect populations were monitored before and after treatment. Periodic sweep-net collections and examination of the leaves in treated and untreated broccoli plots revealed mean reductions of P cruciferae levels of nearly 98% 1 week post-application compared with untreated plots. The residual toxicity of esfenvalerate was also effective for 2 weeks in reducing population density of P rapae by 69% on broccoli leaves. The impact of esfenvalerate on feeding damage to broccoli leaves was established by counting the number of feeding holes made by P cruciferae on spring broccoli and P rapae on fall broccoli. As the leaf area ingested increased, a linear relationship was seen between the number of holes and number of insects. Results indicated that forage destruction by the two pests was significantly reduced by esfenvalerate application. Esfenvalerate was extracted from broccoli at 1 h and 1, 3, 7, 10, and 14 days post-application for residue analysis. Residues on spring broccoli were 12.2, 5.2 and 2.9 micrograms cm-2 on the leaves and 0.13, 0.05 and 0.02 microgram g-1 on the heads at 1 h, 1 and 3 days, respectively. Only trace levels (0.001 microgram g-1) were detected in/on the heads 14 days after spraying. On the basis of half-life (T1/2) values, persistence of esfenvalerate on spring broccoli leaves (T1/2 = 1 day) was shorter than on fall broccoli (T1/2 = 1.6 days). T1/2 values were 2.1 and 3.6 days on spring and fall broccoli heads, respectively. The implications of these residue levels on re-entry times into treated fields are discussed.

Production of methyl ketones as naturally occurring insecticides from wild tomato accessions is explored in this study. Density of two glandular trichomes (type IV and type VI) on the leaves of six wild tomato accessions of Lycopersicon hirsutum f. glabratum (Mull); three accessions of L. hirsutum f. typicum (Humb & Bonpl.); two accessions of L. pennellii Corr. (D'Arcy); and density of type VI glandular trichomes of the commercial tomato Lycopersicon esculentum cv. Fabulous are reported. Densities of type IV and VI glandular trichomes varied among the accessions tested. Type IV trichomes occurred at much higher densities than type VI. Over all accessions and counting trichome densities on both abaxial and adaxial leaflet surfaces, type IV densities averaged 96,378 trichomes.g(-1) leaflets while type VI densities averaged 67,350 trichomes.g(-1) leaflets. Concentrations of four methyl ketones (2-tridecanone, 2-dodecanone, 2-undecanone, 2-pentadecanone) were determined per unit leaf surface area (mm2) and per g fresh leaflets. Concentrations of total methyl ketones ranged from 81.3 microg.g(-1) fresh leaflets on L. esculentum cv. Fabulous to 5.5 mg.g(-1) on L. hirsutum f. glabratum (PI 134417). Two methyl ketones, 2-undecanone and 2-tridecanone, predominated trichome secretions in five of the L. hirsutum f. glabratum accessions tested (PI 251304, PI 126449, PI 134417, PI 134418, and LA 407).

Land productivity can decline when top soil is lost. In Kentucky, limited resource farmers often produce vegetable crops on erodible lands. The objectives of this study were 1) to quantify the impact of three soil management practices (SMPs) on quantity of potato produced on erodible land, 2) to evaluate the impact of pyrethrin and azadirachtin insecticides on potato tuber quality, and 3) to assess the impact of yard waste compost on the chemical composition (ascorbic acid, free sugars, phenol contents) of potato tubers. Potatoes (Solanum tuberosum L. cv. Kennebec) were grown in a silty loam soil of 10% slope. Plots (n= 18) were 3.7 m wide and 22 m long (10% slope), with metal borders of 20 cm above ground level. Two botanical insecticides, Multi-Purpose Insecticide (containing pyrethrin 0.2%) and Neemix 4EC (containing 0.25% azadirachtin) were sprayed twice on potato foliage during each of two growing seasons (1997 and 1999) at the recommended rates of 6 lbs and 2 gallons.acre(-1), respectively. The SMPs were tall fescue strips (FS) intercropped between each two potato rows, soil mixed with yard waste compost (COM) and no-mulch (NM) treatment (roto-tilled bare soil). The experimental designwas a 2 x 3 x 3 factorial with main factors of two insecticides and three SMPs replicated three times. Average potato yield was lowest in NM and FS and highest in COM treatments. Yield obtained from the bottom of the plots was greater than that obtained from the top of plots. Tuber defects (rot, scab, sun green, hollow heart, necrosis, and vascular discoloration) were significantly different between the two growing seasons. The two insecticidal treatments did not have much influence on potato yield or tuber defects. Tubers obtained from tall fescue treatments had low levels of ascorbic acid and reducing sugars compared to compost treatments.

Residues of pyrethrin-I (Py-I) and pyrethrin-II (Py-II), the major insecticidal components of the pyrethrum daisy (Tanacetum cinerariifolium) as well as residues of piperonyl butoxide (PBO, a pyrethrum synergist) were determined in soil and on potato foliage grown under field conditions. A pyrethrum formulation (Multi-Purpose Insecticide) containing the three active ingredients was sprayed twice at the rate of 6 lbs of formulated product.acre(-1) ( 5.4 and 27.2 g A.I. of pyrethrin and PBO, respectively) on potato foliage during the growing season. In soil, three management practices (yard waste compost, grass filter strips, and a no mulch treatment) were used to study the impact of surface soil characteristics on the amount of pyrethrins (Pys) and PBO retained in soil. Soil samples and potato leaves were collected at different time intervals after spraying. Samples were purified and concentrated using solid-phase extraction columns containing C18-Octadecyl bonded silica. Residues were quantified by high-performance liquid chromatograph equipped with a UV detector. The first spray resulted in mean initial deposits of 0.18, 0.40, and 0.99 microg.g(-1) potato leaves for Py-I, Py-II, and PBO, respectively. Residues in soil were higher in compost treatments compared to no mulch treatments.

Simultaneous analysis of pyrethrins (Py-I and Py-II) and piperonyl butoxide (PBO) in soil and runoff water samples following field application of a new pyrethrum formulation containing pyrethrins (Py's) and PBO is described. Residues of total Py's and PBO were extracted from soil samples using hexane-acetone (9:1). A solid phase extraction (SPE) column containing C18-octadecyl bonded silica was used to separate Py's and PBO residues from runoff water. Residues in soil and water were quantitated by high performance liquid chromatography (HPLC) equipped with C18-column and a UV detector. Concentration of Py-II in soil was 100 times higher than that of Py-I 1 h following treatment and 9.6 times higher than Py-I in runoff surface water 11 days following treatment. Results indicated that Py's are non-persistent in soil (even though lipophillic) and water when applied at the recommended rate of 6 lbs (5.31 g A.I.) per acre. There was a consistent decrease in total Py's residues as time after spraying increased. Py's residues in soil decreased from 0.91 to 0.11 ppm 4 days following treatment and one month after treatment only 0.002 ppm were detected. The highest concentration of Py's in runoff water was 36.09 ng/liter following the first rainfall (11 days following treatment). PBO initial residues detected in soil samples were low (0.84 microgram/g soil) while no residues of PBO were detected in runoff water.