scholarly journals Interaction between biological and chemistry fungicides and tomato pollinators

2018 ◽  
Vol 12 (2) ◽  
pp. 425-435
Author(s):  
Carlos De Melo e Silva-Neto ◽  
Anna Clara Chaves Ribeiro ◽  
Flaviana Lima Gomes ◽  
Jordana Guimarães Neves ◽  
Aniela Pilar Campos de Melo ◽  
...  

The use of agrochemicals is harmful to bees visiting agricultural crops, reducing production gains from pollination, but the effect of fungicides on these bees is not known. The objective of this study was to verify the effect of bee visitation influenced by different fungicides on the tomato crop and on the deposition of pollen grains on the stigma, number of seeds, mass and fruit size. The experiment was conducted with 10 treatments: (T1) control treatment, without application of agrochemicals; (T2 and T3) Bacillus subtilis in different application frequencies; (T4) copper hydroxide; (T5) B. subtilis and copper hydroxide; (T6) acibenzolar-S-methyl; (T7) (trifloxystrobin+tebuconazole) and B. subtilis; (T8) copper hydroxide+Mancozeb; (T9) propineb+(trifloxystrobin+ tebuconazole); (T10) (trifloxystrobin+tebuconazole)+B. subtilis+copper hydroxide. The presence of the pollination mark on the flower, the pollen load of the stigmas, the number of seeds per fruit, and the size and mass of the fruits were determined in each treatment. Subsequently, the mortality rate of Melipona quadrifasciata (Hymenoptera, Apidae) exposed to four fungicides (trifloxystrobin+tebuconazole; manganese and zinc; copper hydroxide; Bacillus subtilis) was estimated. The mortality rate of M. quadrifasciata over 24 h of evaluation was higher in the treatments with copper hydroxide and trifloxystrobin+tebuconazole (75 and 50%, respectively). The mortality rate was lower in the treatments with manganese and zinc and Bacillus subtilis and in the control treatment. The treatments with trifloxystrobin+tebuconazole reduced the presence of bite marks on the flowers and of pollen grains on the flower stigma. The fruits of the control treatments and treatments with B. subtilis and copper hydroxide were larger and had greater mass, as compared to other agrochemicals. Thus, a higher number of pesticide applications on the tomatoes reduced bee visitation rates to the flowers and, consequently, reduced the amount of pollen grains deposited on the stigmas, also reducing the fruit production. 

2018 ◽  
Vol 36 (1) ◽  
pp. 88-93
Author(s):  
Ricardo S Bezerra ◽  
Adão Wagner P Evangelista ◽  
José Alves Júnior ◽  
Abadia R Nascimento ◽  
Derblai Casaroli

ABSTRACT The application of high level of fertilization and inadequate management of fertigation in tomato crop can promote increase of salinity of the solution, nutritional imbalance and physiological disorders in the plants, consequently reduces the productivity and the quality of the fruits. The aim of this study was to evaluate different fertigation strategies in growth and production of mini tomato plants cultivated with substrate in a greenhouse. The experimental design was in randomized complete blocks with four treatments and twenty replicates. The treatments corresponded to four fertigation strategies, as follows: T1 [(control) fertigation with leaching of 20%]; T2 fertigation throughout the day and irrigation at the end of the day with leaching of 20%; T3 irrigation with leaching of 20%, followed by fertigation in all activations of the irrigation system; T4 fertigation with leaching of 20% and reuse of the leached solution. Stem height and diameter, number of clusters, total and commercial fruit production, fruit size, fruit color, total titratable acidity, soluble solids content and fruit texture were evaluated. No significant differences were detected among the treatments in relation to the growth variables of the mini tomato plants. The strategies of fertigation tested do not influence significantly the growth of tomato plants. The T1 and T4 managements provide higher commercial production and fruits with higher content of soluble solids when compared with other management strategies evaluated. Considering the nutritional factor, we recommend to reuse the nutrient solution used in the tomato cultivation with substrate, correcting daily the electrical conductivity of the solution.


Agronomy ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1141
Author(s):  
Kimberly A. Stoner

Pumpkins and winter squash require insect pollination to set fruit, but only three bee species are important pollinators of these crops in the Northeastern US. To determine if natural levels of pollen deposition are sufficient for full fruit production, open pollination was measured by counting pollen grains on stigmas, and open pollination was compared to supplemental hand pollination for fruit set, fruit size, and seed number. A threshold of 2300 pollen grains per stigma was sufficient for full pollination and fruit production. This threshold was met in 79 out of 80 combinations of site and sample date over four years on farms across Connecticut with a wide range of field sizes and pest management practices. Along with stigma collection, bees per flower were counted hourly on 100 flowers along a transect. Counts of bumble bees on female flowers were more closely related to the amount of pollen deposited than counts of bees on all flowers or counts of honey bees or squash bees on female flowers. There was tremendous variation in abundance of the three bee species on female flowers across farms within a year and even among years on a single farm.


Growth regulators, phytohormones, both natural and artificial, are the main means to control plant ontogenesis. They are involved in regulating the processes of cell differentiation and cell divisions, the formation of tissues and organs, the changes in the rate of growth and development, the duration of the certain stages of ontogenesis. The main classes of phytohormones used in plant biotechnology, in particular, in the induction of haploid structures, are auxins and cytokinins. The mechanism of action of phytohormones on a cell is rather complicated and may have a different character. Understanding the characteristics of the action of phytohormones is complicated by the fact that the system of hormonal regulation of plant life is multicomponent. This is manifested in the fact that the same physiological process is most often influenced not by one, but by several phytohormones, covering a wide range of aspects of cell metabolism. In connection with the foregoing, the purpose of our work was to test a set of nutrient media with different basic composition and different proportions of phytohormones to determine the patterns of their influence on the processes of haploid structure induction in rape anther culture using accessions, developed at the Institute of Oilseed Crops NAAS. The material used was two accessions of winter rapeseed (No. 1 and No. 2) and one sample of spring rapeseed, provided by the Rapeseed Breeding laboratory of the Institute of Oilseed Crops. Incised inflorescences were kept against the background of low temperature of 6–8 ° C for several days, and then, under aseptic conditions, anthers with unripe pollen grains were isolated and planted on nutrient media differing in both basic mineral composition and content of phytohormones. MS (Murashige & Skoog 1962) and B5 (Gamborg et al 1968) media were used as basic media. Phytohormones were added to the basic media in various combinations – BA, 2,4-D, NAA at the concentrations of 0.1-0.6 mg/l. In each treatment up to 300 anthers were cultivated. Differences between treatments were evaluated using standard t-test. Studies have shown that in the anther culture of rapeseed on the tested nutrient media, morphogenic structures of different types (embryoids and callus) were originated. Synthetic auxin 2,4-D, regardless of the composition of the basic medium, caused the formation of structures of both types, though with a low frequency. Phytohormone BA of the cytokinin type had a similar effect. In this case, the frequency of structures was slightly higher, and the developed structures were represented mainly by embryoids. The joint action of cytokinin and auxin was the most favorable for the initiation of morphogenic structures. Such combination of phytohormones caused the formation of these structures with a frequency of 24.5-14.7% in the studied genotypes of winter rape. A similar effect of phytohormones on the induction and development of morphogenic structures was also observed in spring rape. In this case, a single basic MS medium was used. The experiment included treatments where phytohormones were absent (control), as well as various combinations of auxin and cytokinin. In the control treatment, the formation of new structures was not noted. In treatments with phytohormones, in addition to the medium with the combination of auxin and cytokinin, the medium in which only cytokinin was present was also rather effective. The treatment in which the action of auxin 2,4-D was combined with the action of another auxin, NAA, turned out to be practically ineffective. Thus, it was found that for the induction of morphogenic structures from microspores in rape anther culture of the tested genotypes, the combination of cytokinin with auxin, or the use of only single cytokinin BA without other phytohormones, had the most positive effect.


HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 548a-548 ◽  
Author(s):  
D.M. Glenn ◽  
G. Puterka ◽  
T. Baugher ◽  
T. Unruh ◽  
S. Drake

Hydrophobic particle film technology (HPF) is a developing pest control system for tree fruit production systems. Studies were established in Chile, and Washington, Pennsylvania, and West Virginia in the United States, to evaluate the effect of HPF technology on tree fruit yield and quality. Studies in Chile, Washington, and West Virginia demonstrated increased photosynthetic rate at the leaf level. Yield was increased in peaches (Chile) and apples (West Virginia), and fruit size was increased in apples (Washington and Pennsylvania). Increased red color in apple was demonstrated at all sites with reduced russetting and `Stayman' cracking in Pennsylvania. HPF technology appears to be an effective tool in reducing water and heat stress in tree fruit resulting in increased fruit quality.


HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 459d-459
Author(s):  
Fumiomi Takeda ◽  
Paul R. Adler ◽  
D. Michael Glenn

Strawberry plants (cvs. Camarosa, Chandler, Sweet Charlie, Primetime, Jewel, and Tribute) were grown in soilless culture systems in a greenhouse from October to May. Fresh-dug and runner-tip Aplug® plants were transplanted into two systems: vertically stacked pots (24 plants/m2) containing perlite and horizontal nutrient film technique troughs (13 plants/m2). Plants were fertigated continuously with recirculating nutrient solution. In a 7-month production cycle, the plug plants bloomed earlier and produced more fruit during the first month of harvest (December) than the fresh-dug plants. Higher yields from plug plants were a result of more fruit numbers and not larger fruit size. Fruit production averaged 6.0 and 3.5 kg/m2 in the trough and pot systems, respectively. The vertical growing system allows greater plant densities, but light intensity reaching the plants in the lower sections of the tower can be less than 20% of levels measured at the top. Establishment costs of protected culture systems are higher, but production is earlier and labor costs are typically reduced. Greenhouse hydroponic culture systems could extend the winter strawberry production to more northern locations.


Agriculture ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 321 ◽  
Author(s):  
Julie Oustric ◽  
Radia Lourkisti ◽  
Stéphane Herbette ◽  
Raphaël Morillon ◽  
Gilles Paolacci ◽  
...  

Current climatic upheavals reduce water availability which impacts the growth and fruit quality of plants. In citrus crops, scion/rootstock combinations are used to ensure high fruit production and quality and a stress tolerance/resistance. Our objective was to assess the effect on the clementine scion (C) under natural mild water deficit of (i) polyploid rootstocks by comparing the allotetraploid FlhorAG1 (C/4xFLs; trifoliate orange + Willowleaf mandarin) with its diploid parents, trifoliate orange (C/2xTOs), and Willowleaf mandarin (C/2xWLs), and with a diploid genotype used as reference (Carrizo citrange, C/2xCCs), (ii) rootstock propagation methods by comparing trifoliate orange seedling (C/2xTOs) with cutting (C/2xTOc). A mild water deficit observed under orchard conditions during the summer period (July–August) induced a significant change in yield (except in C/2xTOs), fruit size, and quality. C/2xCCs, C/2xTOs, and C/2xWLs appeared less affected by water deficit as indicated by their lower reduction of predawn leaf water potential (Ψpd), relative water content (RWC), transpiration (E), and photosynthetic parameters (Pnet and gs). Their greater redox balance was probably due to their better antioxidant efficiency. Seedling rootstocks lead to a better adaptation of clementine scions to water deficit than cutting or allotetraploid rootstock. Improving the tolerance to water deficit requires taking into consideration the rootstock genotype, propagation method, and ploidy level.


Horticulturae ◽  
2021 ◽  
Vol 7 (4) ◽  
pp. 62
Author(s):  
Tae-Kwon Son ◽  
Md Munir Mostafiz ◽  
Hwal-Su Hwang ◽  
Nguyen Truong Thạnh ◽  
Kyeong-Yeoll Lee

In various orchard fruit trees, thinning of blossoms and fruits is important to increase fruit size and quality and to promote a new bloom in the following season. Several chemical thinning agents are currently commercially available, but they are inconsistent and produce side effects in crop plants and insect pollinators. Because of environmental concerns, developing alternative eco-friendly bloom thinning agents is necessary. We developed an eco-friendly bloom thinning formulation (BTF) using minerals and extracts of various medicinal plants. Our BTF spray (0.1%, <i>w/v</i>) decreased the number of fruits per tree (46.5%) and fruit yield per tree (81.5%) but increased the fruit weight (196.8%) compared with the control treatment; the spray induced a small number of larger mango fruits in the treated trees. We also investigated the effect of BTF on the olfactory behavior of <i>Apis mellifera</i> L. (Hymenoptera, Apidae), a major insect pollinator. We analyzed the behavioral changes of adult workers at two different concentrations (0.1% and 1%) of nine different BTF spray components using a Y-tube olfactometer. The behavioral responses of honey bees to nine BTF components showed significant differences. However, honey bees showed no clear attraction or repellent behavior towards the tested BTF components. Our results suggest that the newly developed eco-friendly BTF is practically applicable in mango orchards without interrupting honey bee behavior.


2001 ◽  
Vol 61 (3) ◽  
pp. 449-454 ◽  
Author(s):  
F. A. RAMOS ◽  
I. MARTINS ◽  
J. M. FARIAS ◽  
I. C. S. SILVA ◽  
D. C. COSTA ◽  
...  

Oviposition and predation levels by Speciomerus revoili bruchid beetles were quantified on fruits and seeds of the macaúba palm, Acrocomia aculeata, collected from below mother-trees within the Sarah Kubitschek Park of Brasília, DF, Brazil. A maximum of 12 eggs per fruit were found, with high variations observed between samples. No clear pattern was found for the distribution of the number of eggs per fruit, perhaps due to the artificial conditions of the study area, the absence of dispersers and/or the plasticity in the oviposition behavior of the insect. The number of eggs per fruit was not related to fruit size, but was associated with their availability under the tree-mother. This suggests that the density of eggs per fruit is a balance between the availability of this resource and the number of females in the beetle population. The observed mortality rate, from the egg phase to the final larval stages, was over 75%. About 40% of the seeds of Acrocomia aculeata were predated by Speciomerus revoili.


2015 ◽  
Vol 47 (3) ◽  
pp. 117 ◽  
Author(s):  
M.W. Khudhair ◽  
M.Z. Khalaf ◽  
H.F. Alrubeai ◽  
A.K. Shbar ◽  
B.S. Hamad ◽  
...  

Virulence of entomopathogenic fungi <em>Metarhizium anisopliae</em> and <em>Beauveria bassiana</em> were tested against Arabian Rhinoceros Beetle, <em>Oryctes agamemnon arabicus</em> larvae. Four concentrations (1×10<sup>5</sup>, 1×10<sup>7</sup>, 1×10<sup>9</sup> and 1×10<sup>11</sup> conidia/mL<sup>–1</sup>) of two locally isolated entomopathogenic fungi spore suspensions were used in this study via larval direct spraying. Results revealed that both isolates can cause high mortality rate reaching 100% after 29 days. However, <em>Beauveria bassiana</em> scored higher mortality rate in short time especially at the concentration of 1×10<sup>11</sup> conidia/ mL<sup>–1</sup> with lethal time (LT)<sub>50</sub> 12.75 and LT<sub>90</sub> 20.00; while, <em>Metarhizium anisopliae</em> caused the higher percentage of malformed adults. Moreover, both isolates affected insect’s life cycle particularly in the pupal stage which was reduced remarkably by almost 50% in comparison with the control treatment.


2008 ◽  
Vol 88 (1) ◽  
pp. 165-174 ◽  
Author(s):  
J. A. Cline ◽  
C. G. Embree ◽  
J. Hebb ◽  
D. S. Nichols

Vegetative growth control of apples (Malus × domestica Borkh.) is necessary to maintain a balance between growth and cropping. Pruning is a labour-intensive management practice to achieve this and intrinsically stimulates new growth. Prohexadione-calcium (PC) is a plant bio-regulator that effectively regulat es the shoot extension growth of apples and other tree fruits. Previous research has demonstrated that its efficacy can vary based on the use of spray surfactants and adjuvants. This study investigated the efficacy of two rates of Apogee™, the commercial form of PC, used in combination with the spray surfactants Sylgard 309 and LI 700, on extension shoot growth and yield parameters. Experiments were conducted in Ontario on Empire and Nova Scotia on Royal Court™ Cortland apples. Treatments of 0, 75 or 125 mg L-1 PC, with and without either 0.5% (vol/vol.) LI 700 surfactant or 0.05% (vol/vol) Sylgard 309 surfactant were applied to Empire trees, and 75 or 125 mg L-1 PC, with or without 0.5% (vol/vol) LI 700, were applied to Royal Court™ trees. An untreated control treatment was also included for comparison purposes. A total of two sprays were applied to the Empire trees and a total of three sprays were applied to the Royal Court™ trees. PC significantly decreased the vegetative growth of Empire and Royal Court™ trees by approximately 18 to 44%, respectively, and the efficacy of PC was enhanced when combined with either Sylgard 309 or LI 700 surfactant. No additional benefit in vegetative growth control was gained when using Apogee™ at rates of 125 mg L-1 PC, relative to 75 mg L-1 PC. The rate of Apogee™ did not influence the number of fruit or yield per tree or mean fruit size of either cultivar. For Empire, LI 700 and Sylgard 309 significantly reduced the number of fruit per tree, resulting in lower yields and crop densities. In addition, higher mean fruit weights, and a greater distribution of fruit in the larger size categories were observed for LI 700. Fruit from Royal Court trees treated with the highest rate of Apogee™ had higher crop densities, poorer coloured fruit, and a higher percentage of fruit less than 60 mm in diameter. These data provide support for the use of alternative surfactants with Apogee™ other than those listed on the US and Canadian product labels. Key words: Apogee™, Empire, Cortland, Regalis, calcium 3-oxido-5-oxo-4-propionylcyclohex-3-enecarboxylate, surfactant


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