scholarly journals Tolerance of Southern Pine Seedlings to Clopyralid

2000 ◽  
Vol 24 (1) ◽  
pp. 51-56 ◽  
Author(s):  
David B. South

Abstract Tolerance of three pine species to postemergence applications of clopyralid was examined at ten southern nurseries over a 2 yr period. The herbicide was applied at various times during May, June, and July. At time of lifting, seedling morphology was evaluated (root-collar diameter, shoot height, root dry weight, and shoot dry weight). Loblolly pine (Pinus taeda L.), slash pine (P. elliottii Engelm. var. elliottii) and longleaf pine (P. palustdds Mill.) were tolerant to 210 to 840 g acid equivalent (ae)/ha. However, epinasty was occasionally observed on both loblolly pine and slash pine. The injury symptoms were ephemeral and seedlings appeared normal 3 months after treatment. Results from these tests suggest some pine species are tolerant to this herbicide at the seedling stage. As a result of this research, this herbicide can be legally used in many southern pine nurseries to control troublesome weeds such as sicklepod (Cassia obtusifolia L.), Florida beggerweed (Desmodium tortuosum [Sw.] DC.), horseweed (Erigeron canadensis L.) and other annual broadleaf weeds. South. J. Appl. For. 24(1):51-56.

Plant Disease ◽  
2002 ◽  
Vol 86 (7) ◽  
pp. 803-807 ◽  
Author(s):  
Stephen W. Fraedrich ◽  
Michelle M. Cram

A Longidorus species was consistently associated with patches of stunted and chlorotic loblolly pine seedlings at a forest-tree nursery in Georgia. Seedlings from affected areas had poorly developed root systems that lacked lateral and feeder roots. Longidorus population densities in composite soil samples from the margins of patches ranged from 9 to 67 nematodes per 100 cm3 of soil. In a growth chamber experiment, seedling root dry weight decreased with respect to the initial Longidorus dose as well as the final Longidorus populations in containers. The dry root weight of seedlings were 0.117, 0.090, 0.066, and 0.065 g in containers initially infested with 0, 50, 100, and 200 Longidorus, respectively. Lateral and fine roots were lacking on seedlings at the highest doses. Populations of Longidorus increased in all containers during the experiment. Damage to loblolly pine seedlings caused by Longidorus is a previously undescribed problem in southern pine nurseries. Proper diagnosis of the problem by nematode testing laboratories may require the use of extraction techniques specific for larger nematodes such as Longidorus.


1976 ◽  
Vol 6 (4) ◽  
pp. 453-458 ◽  
Author(s):  
Yasuomi Tanaka ◽  
J. D. Walstad ◽  
J. E. Borrecco

Second-year Douglas fir and 1st-year loblolly pine nursery stock were undercut and wrenched while actively growing in nursery beds. Their morphology and field performance were compared with Douglas fir seedlings that had been undercut only and with loblolly pine seedlings that had been left intact.The treatment produced shorter, thinner-stemmed loblolly pine seedlings with reduced shoot dry weight. Height, diameter, and shoot dry weight of Douglas fir seedlings were virtually unaffected, but root dry weight was increased substantially. Development of fibrous lateral roots was stimulated in both species. As a consequence, shoot–root ratios were considerably improved, and the seedlings were better conditioned to withstand outplanting. On droughty sites, field survival of Douglas fir was increased by 20 percentage points and loblolly pine by 30 percentage points. Wrenching also extended by several weeks the fall and spring planting periods for loblolly pine and the fall planting period for Douglas fir.


1982 ◽  
Vol 6 (2) ◽  
pp. 93-99 ◽  
Author(s):  
Richard W. Guldin

Abstract Loblolly (Pinus taeda L.) and slash pine (P. elliottii Engelm.) seedlings can be grown in Number 2 Styroblock containers in timber-truss greenhouses for essentially the same cost per thousand as bare-root seedlings, if construction of a new nursery is contemplated. Because of the time required to expand a bare-root nursery, every additional dollar spent to expand output using a container facility at the existing location is rewarded with $5.90 in present-worth benefits.


1996 ◽  
Vol 26 (10) ◽  
pp. 1715-1723 ◽  
Author(s):  
R.A. Reinert ◽  
S.R. Shafer ◽  
G. Eason ◽  
S.J. Horton ◽  
M.M. Schoeneberger

Acidic rain and ozone (O3) may have serious consequences on the growth and development of loblolly pine (Pinustaeda L.), a tree species of major economic importance in the southeastern United States. In two independent studies, seedlings of open-pollinated families of loblolly pine were exposed to five concentrations of O3 (0, 80, 160, 240, or 320 nL•L−1) and three simulated rain acidities (pH 5.3, 4.3, or 3.3). Following 23 weeks of growth (12 weeks in charcoal-filtered air and 11 weeks of O3 and simulated acidic rain exposures), stem height, secondary needle dry weight, top and total seedling dry weight, and root/shoot dry weight ratio all were related negatively and linearly with O3 concentration. Stem diameter and root dry weight were also suppressed by O3. Suppression of the growth parameters ranged from 14 to 35% for the greatest O3 concentration. Acidity of simulated rain did not affect seedlings, nor did it affect seedling responses to O3. Results indicate that acid rain probably has little effect on growth of loblolly pine seedlings, but O3 can suppress growth to varying degrees depending on family.


2011 ◽  
Vol 29 (3) ◽  
pp. 125-131
Author(s):  
D. Paul Jackson ◽  
Charles H. Gilliam ◽  
David B. South

Abstract Yellow nutsedge (Cyperus esculentus) is a difficult weed to control in conifer nurseries. Soil fumigation with methyl bromide has been used to control yellow nutsedge for years but may not be available in the future. For this reason, the objective of this research was to identify herbicides that can control yellow nutsedge but do not injure loblolly (Pinus taeda L.) and slash pine (Pinus elliottii Engelm.) when used over-the-top of seedlings. Yellow nutsedge tubers and loblolly and slash pine seedlings were potted separately, and treated with three rates of the herbicides mesotrione (Callisto®), imazosulfuron (Valent-V10142), and halosulfuron (Sedgehammer®). Imazosulfuron and halosulfuron provided the best suppression of nutsedge, but imazosulfuron injured loblolly and slash pine. Slash pine diameter and height growth were reduced by imazosulfuron. Halosulfuron did not affect loblolly pine but it reduced slash pine height growth and the number of new leaders (spring flush growth) the following spring. Mesotrione injured slash pine but provided intermediate control of yellow nutsedge. Halosulfuron applied at 35 to 140 g ai·ha−1 (active ingredient per hectare) over the top of loblolly pine (≥ 60 cm height and ≥ 8 mm diameter) can control yellow nutsedge without injuring pine seedlings.


1990 ◽  
Vol 20 (3) ◽  
pp. 280-284 ◽  
Author(s):  
Jarmo K. Holopainen

The responses of young Scots pine seedlings to mechanical apical meristem damage before and after 4 nights exposure to minimum night temperatures of −2.2 and −6.7 °C in controlled environment growth chambers were compared with control seedlings that were subjected or not to apical meristem damage and exposed to a minimum night temperature of 12 °C. The feeding damage caused by Lygus bugs was simulated by piercing the apical meristem of young pine seedlings with a hypodermic syringe needle and injecting a small drop of distilled water into the wound. At −6.7 °C increased numbers of dead seedlings were found. The proportion of seedlings with multiple leaders greatly increased after piercing, and about half of the seedlings subjected to the apical meristem damage had multiple leaders. The proportion of seedlings with multiple leaders and the number of leader shoots per seedling did not differ among seedlings subjected to apical meristem damage before or after the frost exposure. Short and twisted primary needles occurred in the basal parts of the new shoots in the seedlings with multiple leaders. Seedlings with necrotic needles were most often found after exposure to the night temperature of −6.7 °C. Shoot dry weight and length were significantly lower in seedlings subjected to apical meristem damage after frost exposure than in seedlings subjected to apical meristem damage before frost exposure or to no frost exposure. The results suggest that an increased reduction in growth is to be expected if Lygus bug attacks occur on pine seedlings that already suffer from frost injury.


2016 ◽  
Vol 38 (2) ◽  
Author(s):  
MARCUS VINICIUS SANDOVAL PAIXÃO ◽  
JOSÉ CARLOS LOPES ◽  
EDILSON ROMAIS SCHMILDT ◽  
RODRIGO SOBREIRA ALEXANDRE ◽  
CAROLINE MERLO MENEGHELLI

ABSTRACT This study aimed to evaluate the potential of multi-stems in avocado seeds according to their mass as well as the adventitious rooting of multi-stem budding with or without the use of auxin. The research was carried out at the Vegetation House of Federal Institute of Espírito Santo, Campus Santa Teresa -ES, with seeds of different masses: <60 g, 61 to 80 g, 81 to 100 g and >100 g, in which each experimental unit was made of five seeds, distributed within five repetitions, under a completely randomized design. The seeds were put to germinate and the percentage number of emergence and multiple stems were evaluated. After 150 days, the following evaluations were carried out: survival of rooted cuttings; number of leaves; stem diameter; root length; root volume; root and shoot fresh mass; root and shoot dry mass; shoot height; absolute growth and shoot growth rate; shoot dry weight/root dry mass ratio; shoot height/stem diameter ratio; shoot height/root length and Dickson's quality index ratio. Avocado seeds with mass over 100 g and between 81-100 g presented higher percentage of multiple stems. Rods over 20 cm that were not treated with IBA (indole-3-butyric acid) resulted on avocado plants of better quality. The use of IBA (2000 mg L-1) does not affect the rooting and growth of avocado's multi-stem plants.


2014 ◽  
Vol 23 (3) ◽  
pp. 236-245 ◽  
Author(s):  
Mauritz Vilhelm Vestberg ◽  
Sanna Kukkonen ◽  
Päivi Parikka ◽  
Dan Yu ◽  
Martin Romantschuk

There is increasing global interest in using compost to suppress soil-borne fungal and bacterial diseases and nematodes. We studied the reproducibility of compost suppressive capacity (SC) against Pythium wilt of cucumber using nine composts produced by the same composting plant in 2008 and 2009. A bioassay was set up in a greenhouse using cucumber inoculated with two strains of Pythium. The composts were used as 20% mixtures (v:v) of a basic steam-sterilized light Sphagnum peat and sand (3:1, v:v). Shoot height was measured weekly during the 5-week experiment. At harvest, the SC was calculated as the % difference in shoot dry weight (DW) between non-inoculated and inoculated cucumbers. The SC was not affected by year of production (2008 or 2009), indicating reproducibility of SC when the raw materials and the composting method are not changed. Differences in shoot height were not as pronounced as those for shoot DW. The results were encouraging, but further studies are still needed for producing compost with guaranteed suppressiveness properties.


2001 ◽  
Vol 19 (1) ◽  
pp. 11-14 ◽  
Author(s):  
Wallace G. Pill ◽  
James A. Gunter

Abstract This study was conducted to determine whether treating seeds of ‘Sensation Mixed’ cosmos (Cosmos bipinnatus Cav.) and ‘Bonanza Gold’ marigold (Tagetes patula L.) with paclobutrazol (PB) could suppress seedling growth. Seeds were soaked in solutions of 0, 500 or 1000 mg PB/liter (ppm PB) for 16 hours at 25C (77F) or they were primed [−0.5 MPa (−5 bars) for 7 days at 20C (68F)] in Grade 5 exfoliated vermiculite moistened with 0, 500 or 1000 ppm PB solltuions. Soaked and primed seeds were dried for 1 day at 19C (65F) and 25% relative humidity. These seeds and control (non-treated) seeds were sown into plug cells containing peat-lite. Increasing PB concentration decreased cosmos shoot height at 32 days after planting (DAP), but decreased emergence percentage, responses that were more pronounced with priming than with soaking. A 1 ppm PB growth medium drench [30 ml/cell(0.2 mg PB/cell)] and, to a greater extent a 10 mg PB/liter (ppm PB) shoot spray [2 ml/shoot (0.02 mg PB/shoot)], both applied at 10 DAP, resulted in greater cosmos shoot height suppression at 32 DAP than treatment of seeds with 1000 ppm PB. Soaking marigold seeds in 1000 ppm PB failed to decrease shoot height below those of plants from non-treated seeds at 32 DAP. However, exposure to 1000 ppm PB during priming of marigold seeds resulted in a similar shoot height suppression (13%) as the growth medium drench, and similar shoot dry weight reduction (21%) as the shoot spray. Suppression of shoot growth by this seed treatment was short-term since by five weeks after transplanting into 15 cm (6 in) pots, only marigold plants that had received the growth medium drench or shoot spray were smaller than those of control plants. Treating marigold seeds with 1000 mg ppm PB used about one-fifth the PB used to drench the growth medium.


Weed Science ◽  
1984 ◽  
Vol 32 (4) ◽  
pp. 489-493 ◽  
Author(s):  
Frank L. Young ◽  
David R. Gealy ◽  
Larry A. Morrow

In the greenhouse, glyphosate [N-(phosphonomethyl)glycine] at 0.6 kg ae/ha applied directly to seeds alone or seeds on the soil surface reduced germination and shoot dry weight of common rye (Secale cerealeL. ♯3SECCE). Paraquat (1,1′-dimethyl-4,4′-bipyridinium ion) applied similarly at 0.6 kg ai/ha reduced germination and shoot dry weight of downy brome (Bromus tectorumL. ♯ BROTE) and wheat (Triticum aestivumL. ‘Daws' ♯ TRZAX). Metribuzin [4-amino-6-tert-butyl-3-(methylthio)-as-triazin-5 (4H)-one] at 0.6 kg ai/ha applied to seeds, soil, or seeds and soil had very little effect on germination, but significantly reduced shoot dry weight of common rye, downy brome, wheat, and jointed goatgrass (Aegilops cylindricaHost. ♯ AEGCY). Pronamide [3,5-dichloro(N-1,1-dimethyl-2-propynyl)benzamide] at 0.6 kg ai/ha, and propham (isopropyl carbanilate) at 3.4 kg ai/ha plus extender (p-chlorophenyl-N-methylcarbamate) at 0.4 kg ai/ha substantially reduced shoot height and dry weight of all species, regardless of application method, with pronamide completely inhibiting shoot elongation and dry-weight production in three of the four species.


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