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  • Author or Editor: James A. Reinert x
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Abstract

The oleander aphid, Aphis nerii Fonscolombe, is a common pest of oleander, Nerium oleander L. Acephate, bendiocarb, chlorpyrifos, dimethoate, fenvalerate, methidathion, methomyl, permethrin, phosalone, and pirimicarb provided 100% control for 5 days after one spray application. Dimethoate, fenvalerate, methomyl, and pirimicarb provided additional residual control when plants were reinfested with aphids 5 days posttreatment.

Open Access

Abstract

The tumid spider mite (Tetranyehus tumidus banks) is the most common and destructive spider mite species on palms in nursery and landscape plantings. Treatments with two applications of aldicarb, dienochlor, Tricychohexyltin hydroxide (Dowco-213), propargite, oxythioquinox, and hexakis (beta, beta-dimethylphenethyl)-distannoxane, (SD-14114), left less than 1 mite per 3 leaflet sample on container-grown parlor palms (Chamaedorea elegans Mart.). This degree of control was also obtained but with phytotoxicity by chlordimeform, 0-[5-chloro-1-(methylethyl)-1H-1,2,4-triazol-3-yl] 0,0-diethyl phosphorothioate (CGA-12223), oxamyl, and S-tricyclohexyltin 0, 0-diisopropyl phosphorodithioate (R-28627). Other miticides which caused significant population reduction and no phytotoxicity were acephate and tetradifon. Treatments of chlorobenzilate, dicofol, and formetanate reduced populations significantly but resulted in plant damage.

Open Access

Abstract

Visual evaluations of a 5-year-old replicated planting of 63 zoysiagrass (Zoysia spp.) genotypes in southern Florida showed highly significant (P < 1%) differences in overall vigor and survival, flight selections and 2 commercial cultivars (‘Emerald’ and ‘Meyer’) were sodded at 2 distant sites. Selected genotypes (FZ-28, FZ-80, FZ-26, and FL-1753) were significantly better adapted, had significantly less weed encroachment and greater vigor and ground coverage, than Emerald or Meyer. The latter commercial cultivars were unacceptable in most evaluations. Furthermore, FZ-28 and FZ-80 had low sting nematode (Belonolaimus longicaudatus Rau) counts and FZ-28 had few eggs of Banks grass mite (Oligonychus pratensis [Banks]). Sod webworm (Crambus spp.) infestation appeared to be another variable closely associated with adaptive differences among genotypes and explained serious establishment problems at some sites. Zoysiagrass was successfully established as a turf only on one site involving fumigated soil and generally proved poorly suited for this subtropical region.

Open Access

Abstract

Fifty-two cultivars of cannas (Canna X generalis L.H. Bailey and C. indica L.) were evaluated in a field planting for relative susceptibility to Hippeastrum mosaic (HM), a disease caused by Hippeastrum mosaic virus. The cultivars ‘Mrs. Pierre S. DuPont’ and ‘Pink Gem’ were the most susceptible to HM, while 2 red-leaved cultivars, ‘Wyoming’ and ‘Ambassador’, were highly resistant. Thirty-eight cultivars of cannas grown in containers were evaluated for susceptibility to canna rust (Puccinia thaliae Dietel). The cultivars ‘Halloween’ and ‘Yellow King Humbert’ were highly susceptible to rust, while the most resistant cultivars, ‘Louis Cayeaux’ and ‘La Boheme’, were still moderately susceptible. No single cultivar exhibited good resistance to both HM and rust.

Open Access

Three watermelon [Citrullus lanatus (Thunb.) Matsum & Nakai] cultivars with different ozone (O3) sensitivities were grown in a charcoal-filtered greenhouse and exposed in continuous-stirred tank reactor chambers to five levels (0, 100, 200, 300, or 400 nL·L-1) of sulfur dioxide (SO2) in the presence (80 nL·L-1) or absence (0 nL·L-1) of ozone (O3) for 4 hours/day, 5 days/week for 22 days. In the presence of O3, SO2 increased foliar injury in all three cultivars, but the impact was greatest for the most O3-sensitive cultivar, `Sugar Baby,' moderate for `Crimson Sweet,' and least for the least O3-sensitive cultivar, `Charleston Gray.' For all cultivars, SO2 intensified O3 suppression of leaf area for the first seven mainstem leaves and of dry weights for aboveground and total plant tissues. Root dry weight was independently suppressed by both pollutants, and the root: top ratio was linearly suppressed by SO2 alone. Sulfur dioxide combined with O3 can be detrimental to crop species such as watermelon. Thus, the potential for SO2 phytotoxicity should not be summarily dismissed, especially in the vicinity of SO2 point sources where O3 co-occurs.

Free access

Field (choice) and laboratory (no choice) studies were conducted to evaluate the susceptibility of 12 crape myrtle (Lagerstroemia) cultivars, representing two species and their interspecific hybrids, to feeding damage by the flea beetle (Altica litigata Fall). The results indicate that as a group, the L. indica L. cultivars were more susceptible to attack and significant herbivory damage by Altica beetles, whereas all the L. fauriei Koehne cultivars and most of the interspecific L. indica × fauriei hybrids were resistant. Significant differences in feeding damage were observed between the new and older leaves in the susceptible hybrid ‘Biloxi’ and L. indica ‘Whit IV’, but not in the rest of the cultivars. Mineral nutrient content differences were observed between species with L. indica cultivars having a significantly contrasting nutrient status profile compared with the L. fauriei and interspecific hybrid cultivar groups. The results indicate that the factors influencing Altica flea beetle-feeding preferences and damage are inherited and therefore will allow the implementation of pest management practices that minimize damage and optimize chemical control strategies. In addition, opportunities may exist for breeding and selection efforts that could lead to superior cultivars with insect resistance.

Free access

Watermelon, Citrullus lanatus (Thunb.) Matsum & Nakai cv. Sugar Baby, were grown in the field as a fall crop in open-top chambers (OTC) in southwestern Indiana with either charcoal-filtered (CF) or nonfiltered (NF) air. Ozone and sulfur dioxide were continuously monitored in OTC and ambient air. There was a significant decrease in marketable yield by weight (19.9%, P = 0.05), percentage of marketable fruit by number (20.8%, P = 0.10), and total yield by weight (21.5%, P = 0.05) from plants grown in the NF air treatment compared with those grown in CF air. Ozone-induced foliar injury was significantly greater on plants grown under NF conditions. Ambient concentrations of 03 in southwestern Indiana caused foliar injury (P = 0.10) and significant yield loss to a fall crop of watermelons.

Free access