scholarly journals The Effects of Νatural Enemies on Aphid Populations on Processing Tomato in Central Greece

2017 ◽  
Vol 13 ◽  
pp. 35 ◽  
Author(s):  
Ρ. Lykouressis ◽  
D. CH. Perdikis ◽  
CH. Α. Chalkia
Keyword(s):  
Growing Season ◽  
Aphid Population ◽  
Parasitoid Species ◽  
Tomato Plants ◽  
Central Greece ◽  
Processing Tomato ◽  
Vegetable Products ◽  
Population Peak ◽  
Population Suppression ◽  
Aphid Populations

Two species of aphids, Macrosiphion euphorbiae (Thomas) and Myzus persicae cae (Sulzer) (Homoptera: Aphididae) were the only ones which developed populations on processing tomato in a two year study conducted in central Greece. The aphid population structure showed that M. euphorbiae was much more abundant than M. persicae in both years. The former species peaked in August whilst the latter did not show any particular peak over the two successive years. Some species of natural enemies were recorded. Orius niger Wolff was found in low numbers scattered over a long period but mainly towards the end of the growing season, and it did not correlate with the aphid population. The rate of parasitism of M. euphorbiae by Aphelinus abdominalis Dalman and Praon volucre (Haliday) was very low and it seemed that these two parasitoid species did not have any particular effect on the aphid population suppression. Macrolophus pygmaeus Rambur was the key natural enemy and the most abundant and effective among the predators found. Its highest numbers occurred towards the end of the growing season following the aphid population peak, suggesting a numerical response of this species to its prey. A proportion of the population of M. pygmaeus occurring on tomato plants after fruit harvesting, might he collected and subsequently released in crops such as tomato, pepper and eggplant to biologically control pests in greenhouses, like aphids and whiteflies, thus contributing to the production of healthy vegetable products.

scholarly journals Comparisons Between Alate Aphids Caught in Υellow Water Traps and Aphid Populations on Tomato Plants

2017 ◽  
Vol 11 ◽  
pp. 29 ◽  
Author(s):  
P. Lykouressis ◽  
D. CH. Perdikis ◽  
CH.A. Chalkia ◽  
S. C. Vardaki
Keyword(s):  
Total Population ◽  
Macrosiphum Euphorbiae ◽  
Aphid Population ◽  
Tomato Plants ◽  
Growing Seasons ◽  
Significant Relationships ◽  
Water Traps ◽  
Plant Sampling ◽  
Trap Catches ◽  
Aphid Populations

Aphid monitoring was conducted by means of yellow Moericke water traps placed in tomato fields in two different localities in Co Boiotia during the growing seasons in 1992 and 1993. Additionally, aphid population densities were estimated by plant sampling. Macrosiphum euphorbiae (Thomas) and Myzus persicae (Sulzer) were the only species which developed populations on plants. Regression analysis between the number of alates from traps with either the number of alates or the total aphid population on plants showed that there was no correlation in the case of M. persicae for both localities and years. However, there were significant relationships between the number of alates in traps and either the number of alates on plants (r2=0.83) or the total aphid population on plants (r2=0.69) for M. euphorbiae in 1992. In 1993, such significant relationships were not found for the latter species, most probably due to extremely low trap catches. Significant relationships were also found between alates in traps, during their immigration period, with either alates on plants (r2=0.93) or the total population on plants (r2=0.80) in M. euphorbiae in 1992.

scholarly journals Effects of different methods to control the parasitic weed Phelipanche ramosa (L.) Pomel in processing tomato crops

2016 ◽  
Vol 10 (1s) ◽  
pp. 39 ◽  
Author(s):  
Grazia Disciglio ◽  
Francesco Lops ◽  
Antonia Carlucci ◽  
Giuseppe Gatta ◽  
Annalisa Tarantino ◽  
...  
Keyword(s):  
Control Strategies ◽  
Block Design ◽  
Soluble Solids ◽  
Marketable Yield ◽  
Department Of Agriculture ◽  
Parasitic Weed ◽  
Complete Control ◽  
Tomato Plants ◽  
Processing Tomato ◽  
Phelipanche Ramosa

The root-parasitic weed <em>Phelipanche ramosa</em> (L.) Pomel represents a major problem for processing tomato crops. The control of this holoparasitic plant is difficult, and better understanding of treatment methods is needed to develop new and specific control strategies. This study investigated 12 agronomic, chemical, biological and biotechnological strategies for the control of this parasitic weed, in comparison with the untreated situation. The trial was carried out in 2014 at the Department of Agriculture, Food and the Environment of the University of Foggia (southern Italy), using processing tomato plants grown in pots filled with soil from a field that was heavily infested with <em>P. ramosa</em>. After transplantation, top dressing was performed with 70 kg ha<sup>–1</sup> nitrogen. A randomised block design with 3 replicates (pots) was adopted. During the growing cycle of the tomato, at 70, 75, 81 and 88 days after transplantation, the number of parasitic shoots (branched plants) that had emerged in each pot was determined, and the leaf chlorophyll of the plants was measured using a soil-plantanalysis- development meter. At harvesting on 8 August 2014, the major quanti-qualitative yield parameters were determined, including marketable yield, mean weight, dry matter, soluble solids, and fruit colour. The results show lower chlorophyll levels in the parasitised tomato plants, compared to healthy plants. None of the treatments provided complete control against P. ramosa. However, among the methods tested, Radicon® biostimulant (Radicon, Inc., Elk Grove Village, IL, USA), compost activated with <em>Fusarium oxysporum</em>, nitrogen and sulphur mineral fertilisers, Enzone<sup>TM</sup> soil fumigant (Elliott Chemicals Ltd., Auckland, New Zealand), and a resistant tomato genotype mitigated the virulence of the attacks of this parasite. These effects should be improved by combining some of these treatments, especially for gradual and continued reduction in the <em>seed bank</em> of the parasite in the soil. For the tomato yields across the different treatments, there were no significant differences seen; however, the yields showed an improving trend for treatments with lower presence of the <em>P. ramosa</em> weed.

scholarly journals Fate of nitrogen-15 in the subsequent growing season of greenhouse tomato plants (Lycopersicon esculentum Mill) as influenced by alternate partial root-zone irrigation

RSC Advances ◽  
2017 ◽  
Vol 7 (55) ◽  
pp. 34392-34400 ◽  
Author(s):  
Maomao Hou ◽  
Fenglin Zhong ◽  
Qiu Jin ◽  
Enjiang Liu ◽  
Jie Feng ◽  
...  
Keyword(s):  
Lycopersicon Esculentum ◽  
Root Zone ◽  
Growing Season ◽  
Tomato Plants ◽  
Residual Nitrogen ◽  
Greenhouse Tomato ◽  
Lycopersicon Esculentum Mill ◽  
Crop Uptake ◽  
Previous Season ◽  
Fate Of Nitrogen

Alternate partial root-zone irrigation has profound impacts on the crop uptake of residual nitrogen originated from the previous season.

scholarly journals Differences in growth and yield responses to Aphis gossypii Glover between different okra varieties

2008 ◽  
Vol 43 (No. 3) ◽  
pp. 109-117 ◽  
Author(s):  
H.K. Shannag ◽  
J.M. Al-Qudah ◽  
I.M. Makhadmeh ◽  
N.M. Freihat
Keyword(s):  
Leaf Area ◽  
Aphis Gossypii ◽  
Total Yield ◽  
Dry Weight ◽  
Growing Season ◽  
Growth And Yield ◽  
Experimental Plant ◽  
Local Reduction ◽  
Yield Responses ◽  
Aphid Populations

The reactions of five commercial varieties of okra, <i>Abelmoschus esculentus</i>, to <i>A. gossypii</i> were evaluated under semiarid field conditions. Each experimental plant of varieties Clemson spineless, Clemson spineless 80, Lee, Perkins dwarf, and Local was infested 60 days after emergence by three late-nymphal instars of the aphid. The results showed that aphid populations increased constantly on the varieties, except for days 42 and 49 after infestation, attaining a peak at about the end of the growing season. Differences in aphid densities were recorded between varieties. The aphids were most numerous on var. Local, while lowest in number on var. Lee. Infestation by aphids on okra varieties reduced yield by 57% on var. Perkins dwarf, 56% on var. Lee, 24% on var. Clemson spineless, 21% on var. Clemson spineless 80, and 5% on var. Local. Reduction in the number of pods produced per plant followed the same pattern as observed for total yield. Aphids had not altered significantly the vegetative plant growth at day 37 following infestation. At day 66, a substantial decrease in shoot fresh and dry weights and also leaf area was evident on var. Perkins dwarf while on var. Clemson spineless only the leaf area was significantly reduced. Moreover, aphid-free controls varied widely in their growth and productivity at the end of growing season. Varieties Clemson spineless and Clemson spineless 80 produced the highest total yield and pod numbers, var. Local the lowest. The varieties Perkins dwarf and Clemson spineless produced significantly higher shoot fresh and dry weight, as well as leaf area, than vars. Lee and Local.

Low Water Tensions in Defined Growth Stages of Processing Tomato Plants and their Effects on Yield and Quality

1977 ◽  
Vol 52 (3) ◽  
pp. 391-399 ◽  
Author(s):  
Jehoshua Rudich ◽  
Dov Kalmar ◽  
Chanan Geizenberg ◽  
Stella Harel
Keyword(s):  
Growth Stages ◽  
Tomato Plants ◽  
Processing Tomato ◽  
Yield And Quality

SEASONAL ABUNDANCE OF RED AND GREEN MORPHS OF THE TOBACCO APHID (HOMOPTERA: APHIDIDAE) ON FLUE-CURED TOBACCO IN GEORGIA

1989 ◽  
Vol 24 (4) ◽  
pp. 531-538 ◽  
Author(s):  
Robert M. McPherson
Keyword(s):  
High Temperatures ◽  
Field Experiments ◽  
Aphid Population ◽  
Seasonal Abundance ◽  
Population Increase ◽  
Population Densities ◽  
Early Season ◽  
Myzus Nicotianae ◽  
Aphid Populations ◽  
Tobacco Aphid

The seasonal abundance of red and green morphs of the tobacco aphid, Myzus nicotianae Blackman, was investigated on flue-cured tobacco in Georgia during 1987–1988. The effect of tobacco transplantation date also was examined in 1988. Aphid populations peaked on tobacco in mid-June 1987, then rapidly declined following the removal of the terminal floral branch (topping). Early season samples contained both green and red morphs; however, by early June, and throughout the remainder of the season, the aphid population was almost exclusively comprised of the red morph. Similar results were obtained in 1988, although population densities were higher and peaked earlier in the early transplanting (30 March) compared to the 14 April and 28 April transplantings. Regardless of transplanting date, the red morphs began a rapid population increase about 45 days after transplantation, and this increase continued until plants were topped. Daily high temperatures exceeding 35°C did not appear detrimental to the red morphs in these field experiments.

scholarly journals Parasitism of Tuta absoluta in tomato plants by Trichogramma pretiosum Riley in response to host density and plant structures

2008 ◽  
Vol 38 (6) ◽  
pp. 1504-1509 ◽  
Author(s):  
Cristina Arantes Faria ◽  
Jorge Braz Torres ◽  
Adriana Maria Vieira Fernandes ◽  
Angela Maria Isidro Farias
Keyword(s):  
Host Density ◽  
Tuta Absoluta ◽  
Plant Canopy ◽  
Trichogramma Pretiosum ◽  
Parasitism Rate ◽  
Tomato Plants ◽  
Processing Tomato ◽  
Upper Third ◽  
Oviposition Sites ◽  
Host Patch

One important factor determining the efficacy of parasitoids is the way they exploit different host patch. This study evaluated the response of females of Trichogramma pretiosum Riley (Hymenoptera: Trichogrammatidae) to the oviposition sites of Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) on processing tomato plants. In fully developed caged tomato plants T. absoluta moths were released, followed by the release of T. pretiosum females 12h later. After 24h of parasitoid release, the moth oviposition sites were mapped according to the plant canopy, and levels of parasitism assessed. The parasitism rate varied from 1.5 to 28%. There was not influence of plant structures on parasitism, except for the absence of parasitism on the plant apex. Levels of both T. absoluta oviposition and parasitism by T. pretiosum were higher on the upper third of the plant, decreasing downward along the plant canopy.

scholarly journals Early Pruning Effects on ‘Florida-47’ and ‘Sungard’ Tomato

2008 ◽  
Vol 18 (3) ◽  
pp. 467-470 ◽  
Author(s):  
Bielinski M. Santos
Keyword(s):  
Plant Height ◽  
Plant Architecture ◽  
Disease Incidence ◽  
Growing Season ◽  
Cultural Practice ◽  
Growth And Yield ◽  
Marketable Yield ◽  
Tomato Plants ◽  
Central Florida ◽  
Tomato Cultivars

The effects of early pruning on the growth and yield of ‘Florida-47’ and ‘Sungard’ tomato (Solanum lycopersicum) were assessed in west-central Florida. Each cultivar was established in separate experiments. The four pruning treatments consisted of leaving one, two, and three main stems in the tomato plants below the first flower cluster, and a nonpruned control. Pruning shoots had significant effects on the plant height of ‘Sungard’ and ‘Florida-47’ at 4 and 3 weeks after transplanting, respectively. Tomato plants with a single stem were 13% and 10% taller than the ones in the nonpruned control, respectively. However, this effect disappeared 1 and 2 weeks later in both cultivars. Regardless of the cultivar, early pruning did not influence foliar disease incidence or early and total tomato marketable yield. This cultural practice did not affect the partitioning to different fruit categories in either cultivars. This data showed that early pruning can temporarily change the plant architecture of ‘Sungard’ and ‘Florida-47’ tomato, explaining the perceived increased plant vigor in comparison with the nonpruned control. However, the effect disappeared during the growing season and did not reflect on marketable yields of either tomato cultivars. If no pruning were performed in these cultivars, growers would be able to save an estimated $40/acre of tomato.

Sign in / Sign up

Export Citation Format

Share Document