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Six cultivars of poinsettia (Euphorbia pulcherrima Wind.), `Angelika White', `Celebrate 2', `Freedom Red', `Lilo Red', `Red Sails', and `Supjibi Red' were grown for 9 weeks during vegetative development under three constant-feed fertilizer treatments, 80,160, or 240 mg N/liter and two irrigation regimes, well-watered (high irrigation) or water deficient (low irrigation). Plants fertilized with 80 or 240 mg N/liter were 10% to 18% shorter, while those fertilized with 160 mg N/liter were 25 % shorter with low versus high irrigation. Leaf area and leaf dry weight increased linearly in response to increasing fertilizer concentrations. Low irrigation reduced leaf area, leaf, stem, and shoot dry weight 3670 to 41%. Cultivars responded similarly to irrigation and fertilizer treatments in all components of shoot biomass production and no interactions between the main effects and cultivars occurred. Stomatal conductance and transpiration decreased with increasing fertilizer rates or sometimes with low irrigation. Highest chlorophyll contents occurred in leaves of `Lilo Red' and `Freedom Red'. Leaves of plants fertilized with 80 mg N/liter were deficient in leaf N and had 40 % to 49 % lower leaf chlorophyll content compared to plants fertilized with 160 or 240 mg N/liter. Irrigation had no effect on leaf N or chlorophyll content. At the end of the experiment leaves of `Supjibi Red' and `Angelika White' contained higher concentrations of soluble proteins than the other four cultivars.

`Fontana', `Iridon', `Pink Lady', `Splendor', `White Diamond', and `White View Time' chrysanthemum (Dendranthema × grandiflorum Ramat.) were grown for 10 weeks with N rates of 80, 160, or 240 mg·L^-1 constant liquid fertilization and irrigated at sufficient (high) or deficient (low) amount. Cultivars differed in growth habit, and treatments significantly affected all variables measured. Plants fertilized with 80 mg·L^-1 had lower leaf and stem dry mass, less leaf area, and were deficient in leaf N compared with plants fertilized with twice the amount of N. The highest stem dry mass was produced with 160 mg·L^-1. Leaf and stem dry mass were reduced 25% for plants receiving low irrigation compared to those receiving high irrigation. In general, leaf area increased when fertilizer was raised from 80 to 160 mg·L^-1 but differed by cultivar and irrigation regime when fertilizer was increased to 240 mg·L^-1. Three weeks after the experiment started, electrical conductivity (EC) of runoff collected weekly from `White Diamond' plants fertilized with 240 mg·L<sup>-1</sup> exceeded the average EC of the irrigation solution. The 240 mg·L<sup>-1</sup> treatment also resulted in excessive EC in the growing substrate at the end of the experiment and reduced stem dry mass by 11% compared with the 160 mg·L<sup>-1</sup> fertilizer regime. Substrate EC differed between cultivars in response to fertilizer and irrigation. Significantly more adult western flower thrips [Frankliniella occidentalis (Pergrande)], 55% and 52%, were found on the foliage of `Pink Lady' and `Fontana', respectively, than on `Iridon'. `Pink Lady' and `Fontana' had more immature thrips at the end of the experiment than `Iridon' and `White View Time'. Fewer adults and immatures were found on plants fertilized with 80 mg·L^-1 than 240 mg·L^-1. Fewer adults were detected in plants under high versus low irrigation, while irrigation had no effect on the number of immatures. The simultaneous use of plant varietal resistance and plant cultural growing techniques has the potential to lower thrips populations on chrysanthemum.

Two experiments were conducted to evaluate the effect of the plant regulator uniconazole on plant height, flowering, and fruit yield of vegetable transplants. In the first experiment, seedlings of tomato (Solanum lycopersicum ‘Early Girl’), pepper (Capsicum annuum ‘Jalapeno’), and eggplant (Solanum melongena ‘Millionaire’), were sprayed with water (untreated control) or with 2.5, 5, and 10 mg·L⁻¹ of uniconazole. Five weeks after treatment (WAT), application of 2.5 mg·L⁻¹ of uniconazole reduced the height of tomato by 17%, and of 5 and 10 mg·L⁻¹, by 25%. The effect of 10 mg·L⁻¹ of uniconazole on tomato plant height persisted until 13 WAT, but did not affect fruit yield. ‘Early Girl’ tomato plants treated with 10 mg·L⁻¹ of uniconazole were still shorter than the untreated control at this time, but there were no significant differences in the number or weight of the fruit produced by the plants treated with 10 mg·L⁻¹ of uniconazole, and the untreated controls. In contrast, as the rate of uniconazole increased, the height of ‘Jalapeno’ pepper and ‘Millionaire’ eggplant decreased. Application of uniconazole had no effect on the number of fruit produced by ‘Millionaire’ eggplant. However, treatment with 10 mg·L⁻¹ of uniconazole reduced the number of fruit produced by pepper plants by 50%, and reduced the total weight of fruit produced by pepper and eggplant plants by 30% and 50%, respectively, compared with the untreated control. The second experiment analyzed the effects of 5, 8, and 10 mg·L⁻¹ of uniconazole on two cultivars of tomato with different growth habit, Early Girl (determinate) and Sun Sugar (indeterminate). Application of all rates of uniconazole decreased plant height but not the final fruit yield of the two tomato cultivars.

Pesticide application is used in horticulture to reduce plant damage from organisms such as insects and mites. Systemic insecticides are highly efficacious and readily taken up by plant tissues. However, pesticide-treated plants may impose risks to nontarget insects or other organisms within ecosystems. In this study, insecticide residues in nectar, leaves, and flower petals of the horticulturally significant herbaceous annual snapdragon, Antirrhinum majus (Lamiales: Plantaginaceae), were assessed at two locations over several weeks following foliar and drench treatment with five systemic insecticides. Concentrations of the insecticides were determined by liquid chromatography–mass spectrometry. The independent effects Application Method, Application Rate, and Time were statistically significant among all active ingredients in the three matrices in both sites in California (CA) and New Jersey (NJ). The interaction effects were also generally statistically significant in the CA site but less consistently so in the NJ site, dependent on the active ingredient and matrix. Post hoc analyses found the highest residue concentrations in leaves and the lowest in nectar, a trend generally consistent over time regardless of active ingredient for both the CA and NJ sites. The results of this study are discussed in the context of conserving pollinators and other beneficial insects. It is recommended that similar studies should be implemented in different geographical regions and climates, along with multiyear studies for perennial ornamental plants.