scholarly journals Uji Pemangsaan dan Tanggap Fungsional Predator Chysoperla carnea Stephens (Neuroptera: Crysopidae) Terhadap Phenacoccus manihoti Matile-Ferrero (Hemiptera: Pseudococcidae)

2021 ◽  
Vol 11 (1) ◽  
pp. 76
Author(s):  
I WAYAN DIRGAYANA ◽  
I WAYAN SUPARTHA ◽  
I NYOMAN WIJAYA

Predation and Functional Response Test of Predator Chysoperla carnea Stephens (Neuroptera: Crysopidae) Against Phenacoccus manihoti Matile-Ferrero (Hemiptera: Pseudococcidae). This study aims to evaluate the predatory capacity of C. carnea by measuring the rate of searching capacity and handling-time of one prey and its functional response to the population density of P. manihoti. The research was conducted at the Integrated Pest Management Laboratory (IPMLab), Faculty of Agriculture, Udayana University. The study was conducted from February to May 2019. Testing of functional responses used a randomized block design with 5 treatments (3, 6, 9, 12, 15 nymphs-3) each of which was repeated 10 times. The results showed that the prey searching-capacity when the population was low (3 nymphs-3) took longer (10.37 minutes), while when the population was high it took a short time (6.23 minutes). The length of time for handling one prey in the low population was 6.08 minutes, while in the high population it was 5.48 minutes. Predator C. carnea has a tpe-2 functional response to an increase in the population of P. manihoti nymphs with the equation Y = 4.32x / 1 + 1.973x (R2 = 0.980). The rate of predation increases sharply when the population of low increases, and decreases when the increase of prey population increases. C. carnea has the potential to be developed as a control agent for P. manihoti.

Author(s):  
Azadeh Farazmand ◽  
Masood Amir-Maafi

Abstract In this research, functional responses of Amblyseius swirskii Athias-Henriot preying on different Tetranychus urticae Koch nymphal densities (2, 4, 8, 16, 32, 64, and 128) were studied at eight constant temperatures (15, 20, 25, 27.5, 30, 32.5, 35 and 37.5°C) in a circular Petri dish (3-cm diameter × 1-cm height) under lab conditions. At all temperatures, the logistic regression showed a type II functional response. A nonlinear relationship was found between temperature and attack rate and the reciprocal of handling time. The reciprocal of handling time decreased exponentially with increasing temperature. In contrast, the attack rate grew rapidly with increasing temperatures up to an optimum, showing a decreasing trend at higher temperatures. In order to quantify the functional response of A. swirskii over a broad range of temperatures and to gain a better estimation of attack rate and handling time, a temperature-settled functional response equation was suited to our data. Our model showed that the number of prey consumed increased with rising prey density. Also, the predation rates increased with increasing temperatures but decreased at extremely high temperatures. Based on our model, the predation rate begins at the lower temperature threshold (11.73°C) and reaches its peak at upper temperature threshold (29.43°C). The coefficient of determination (R2) of the random predator model was 0.99 for all temperatures. The capability of A. swirskii to search and consume T. urticae over a wide range of temperatures makes it a good agent for natural control of T. urticae in greenhouses.


2013 ◽  
Vol 13 (1) ◽  
pp. 18
Author(s):  
W. Setiawati ◽  
N. Gunaeni ◽  
T. S. Uhan ◽  
A. Hasyim

Bemisia tabaci (Gen.) (Homoptera: Aleyrodidae) is one of the most serious pests on tomato. It is mainly controlled by chemi-cal means, requiring some 25 sprays during the average growing season. The extensive and repeated use of insecticides has dis-rupted the natural balance between this pest and its natural enemies. In this study, Menochilus sexmaculatus F. was evalu-ated as a possible biological control agent of B. tabaci and its effect on Gemini virus infestation. The study was conducted at the experimental station of the Indonesian Vegetables Research Institute (IVeGRI) in Lembang, West Java (1,250 m above sea level) from August to December 2008. The experimental plots consisted of 0.35 ha of tomato (± 100 m2 per plot) and spatially separated with four rows of maize (a minimum of 1 m) inter-plot distance to prevent cross-contamination among plots. The experiment was arranged in completely randomized block design with eight treatments and four replications. M. sexmaculatus were released at 24 days after planting. The treatments were designed according dosages and schedules at three released populations (i.e. 10 predators per plot, 20 predators per plot, and 10 predators per plot at vegetative stage followed by 20 predators per plot at generative stage); two places of release (center and edge of the plot); and two schedules of release (weekly and biweekly). Efficacy of the predator was measured in terms of the density of B. tabaci, both before and after release of the predator and its effect on Gemini virus infestation. The result indicated the potential use of M. sexmaculatus to control B. tabaci and its effect on Gemini virus infestation on tomato. Reductions in B. tabaci populations and subsequent tomato yields were significant. B. tabaci population in plots receiving 10 predators showed 73.62% and 75.75% reductions by the end of experiment. The incidence and intensity of Gemini virus were consistently and significantly lowest and tomato yield gain was observed when 10 predators were released at weekly intervals. It is suggested that release of M. sexmaculatus against B. tabaci on tomato may be offered as an alternative solution to increase implementation of biologically-based B. tabaci management. <br /><br />


2022 ◽  
Vol 154 ◽  
Author(s):  
Desh Deepak Chaudhary ◽  
Bhupendra Kumar ◽  
Geetanjali Mishra ◽  
Omkar

Abstract In the present study, we assessed functional response curves of two generalist coccinellid beetles (Coleoptera: Coccinellidae), specifically Menochilus sexmaculatus and Propylea dissecta, using fluctuating densities of aphid prey as a stimulus. In what may be the first such study, we investigated how the prey density experienced during the early larval development of these two predatory beetle species shaped the functional response curves of the late instar–larval and adult stages. The predators were switched from their rearing prey-density environments of scarce, optimal, or abundant prey to five testing density environments of extremely scarce, scarce, suboptimal, optimal, or abundant prey. The individuals of M. sexmaculatus that were reared on either scarce- and optimal- or abundant-prey densities exhibited type II functional response curves as both larvae and adults. However, individuals of P. dissecta that were reared on scarce- and abundant-prey densities displayed modified type II functional response curves as larvae and type II functional response curves as adults. In contrast, individuals of P. dissecta reared on the optimal-prey density displayed type II functional response curves as larvae and modified type II functional response curves as adults. The fourth-instar larvae and adult females of M. sexmaculatus and P. dissecta also exhibited highest prey consumption (T/Th) and shortest prey-handling time (Th) on the scarce-prey rearing density. Thus, under fluctuating-prey conditions, M. sexmaculatus is a better biological control agent of aphids than P. dissecta is.


Author(s):  
Sajjad Dalir ◽  
Hamidreza Hajiqanbar ◽  
Yaghoub Fathipour ◽  
Mostafa Khanamani

Abstract The age-specific functional and numerical responses of Neoseiulus cucumeris Oudemans (Mesostigmata: Phytoseiidae) on eggs of the two-spotted spider mite, Tetranychus urticae Koch (Prostigmata: Tetranychidae), were assessed in the laboratory using bean leaf discs. Densities of 2, 4, 8, 16, 32, 64, and 128 prey were provided to 4- (protonymph), 6- (deutonymph), 8-, 13-, 18-, 23-, 28-, 33-, and 40-d-old N. cucumeris individuals. The functional response of 28- and 40-d-old N. cucumeris fitted type II, whereas the other ages displayed a type III functional response. The longest handling time observed at the age of 4 d was 0.515 h, whereas the shortest handling time and highest value of maximum attack rate (T/Th) were associated with the age of the 28-d-old treatment (0.261 h and 91.95 prey/d, respectively). The numerical response of N. cucumeris showed a significant increase with increasing prey density, but its rate gradually decreased at higher densities. Therefore, the efficiency of conversion of ingested food was relatively higher at low two-spotted spider mite densities, whereas it was reduced at high two-spotted spider mite densities. The stronger functional response and predation capacity of N. cucumeris on two-spotted spider mite eggs indicated the high potential of this predatory mite as an effective biological control agent against two-spotted spider mite especially at its early and middle ages and also when higher prey densities are present.


Animals ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 946 ◽  
Author(s):  
Chao Yu ◽  
Lizhi Zhou ◽  
Nazia Mahtab ◽  
Shaojun Fan ◽  
Yunwei Song

Perceiving how animals adjust their feeding rate under a variety of environmental conditions and understanding the tradeoffs in their foraging strategies are necessary for conservation. The Holling functional response, which describes the relationship of feeding rate and food density to searching rate and handling time, has been applied to a range of waterbirds, especially with regard to Type II functional responses that describe an increasing feeding rate with food density but at a decelerating rate as the curve approaches the asymptote. However, feeding behavior components (feeding rate, searching rate, and handling time) are influenced by factors besides prey density, such as vigilance and flock size. In this study, we aim to elucidate how Bewick’s swans (Cygnus columbianus bewickii) adopt flexible foraging strategies and vary their feeding behavior components in response to disturbance, flock size, and food density. We collected focal sampling data on the foraging behavior of swans that foraged rice grains, foxnut seeds, and tubers in paddy field, foxnut pond, and lake habitats, respectively, in Shengjin and Huangpi lakes during winter from 2016 to 2018. The observed feeding rate was not correlated with food density and displayed a positive relationship with searching rate but negative relationships with handling time, flock size, overall vigilance time, and disturbance time. Handling time was negatively correlated with food density and flock size, yet it increased with disturbance, overall vigilance time, and normal vigilance time. Searching rate was negatively correlated with food density, flock size, and disturbance time. Feeding rate was affected by the combined effects of handling time and searching rate, as well as food density and searching rate. The shape of the observed functional response could not be fitted to Holling’s disc equation. However, the disc equation of the predicted feeding rate of wintering swans was found to be driven by food density. This provides insight into how wintering waterbirds adopt appropriate foraging strategies in response to complicated environmental factors, which has implications for wildlife conservation and habitat management.


Acarologia ◽  
2020 ◽  
Vol 60 (1) ◽  
pp. 30-39
Author(s):  
Fereshteh Bazgir ◽  
Jahanshir Shakarami ◽  
Shahriar Jafari

Eotetranychus frosti and Cenopalpus irani Dosse are pests of apple trees that are widely distributed in apple orchards in Iran. The functional responses and predation rates of Amblyseius swirskii, one of the most commonly utilized phytoseiid mites for biological control, on these two pests were evaluated at 25 ± 1 °C, with 16:8 h L: D, and a relative humidity of 60 ± 10 % on apple leaves. The results of predation rate experiments on the two prey species indicated that the predator consumed significantly more eggs than larvae and protonymphs whereas consumption of deutonymphs were very rare. Likewise, the results of logistic regression analysis showed that A. swirskii exhibited a Type II functional response on all immature stages of E. frosti and C. irani. Handling time (Th) increased as prey size enlarged; the lowest handling times were determined as 0.4858 and 0.3819 h on eggs of E. frosti and C. irani, respectively, whereas the highest were found to be 1.4007 and 1.0190 h on deutonymphs, respectively. Amblyseius swirskii had the higher attack rate coefficient (α) on immature stages of C. irani than E. frosti. Attack rate coefficients (α) varied significantly between life stages of both pests with the highest attack rate obtained on eggs, followed by larvae, protonymphs, and deutonymphs. Results of this study suggest that A. swirskii could be a highly efficient biological control agent of E. frosti and C. irani at least at low prey densities.


2020 ◽  
Vol 10 (1) ◽  
pp. 88
Author(s):  
NI MADE KESUMA DEWI ◽  
I NYOMAN RAI ◽  
I WAYAN WIRAATMAJA

Fertilization Response to Off-Season Production and Fruit Quality of Salak Gula Pasir (Salacca Zalacca cv. Gula Pasir) and water and Chlorophyll Content of Leaves. Naturally salak Gula Pasir (Salacca zalacca cv. Gula Pasir) flowers every three months a year, but only one to two seasons of the flowers can develop into fruit. Failure of flowers develop into fruit, usually call fruit-set failure, causes the fruits be available seasonally in a short time period, only 2-3 months a year, i.e. during the harvest time (on-season period) from December to February. This research aimed to know response of fertilization to off-season production and fruits quality of salak Gula Pasir and its ralatinship to water and chlorophyll content of leaves. The study used a randomized block design with the treatment was fertilization, consists of 14 levels (fertilized according farmers’ way with leaf midrib only/control, fertilized with compost, mycorrhizal biofertilizer, inorganic NPK, combination of farmers' way and compost, combination of farmers’ way and mycorrhizal biofertilizer,  combination of farmers' way and inorganic NPK, combination of compost and mycorrhizal biofertilizer,  combination of compost and inorganic NPK,  combination of mycorrhizal and inorganic NPK,  combination of farmers’ way, compost, and mycorrhizal biofertilizer,  combination of farmers’ way, compost, inorganic NPK,  combination of farmers’ way, mycorrhizal biofertilizer and inorganic NPK, and  combination of farmers’ way, compost, mycorrhizal biofertilizer, and inorganic NPK). Each treatment was repeated 3 times. The study was carried out in the off season period from April to Nopember 2018 at the production center of salak Gula Pasir plantation i.e. at Sibetan Village, Bebandem District, Karangasem Regency. The results showed that the highest fruit weight per tree at the off-season was obtained on combination of fertilization of farmers' way and mycorrhizal biofertilizer  (of 2536.67 g) and the lowest was on  control/fertilized according farmers’ way  (1,220.00 g). Fertilization with compost, mycorrhizal biofertilizer, and inorganic NPK singly, or by combining it, increases the quality of off-season fruit of salak Gula Pasir, reflected by the increase of weight per fruit, fruit diameter and fruit sweetness compared to control. The lower of yield per tree and quality of fruit on control compared to other fertilization treatments was relate to low relative water content and chlorophyll content of leaves.


2020 ◽  
Vol 16 (1) ◽  
pp. 20190758 ◽  
Author(s):  
Robert P. Dunn ◽  
Kevin A. Hovel

The functional response of a consumer to a gradient of resource density is a widespread and consistent framework used to quantify the importance of consumption to population dynamics and stability. Within benthic marine ecosystems, both crustaceans and fishes can provide strong top-down pressure on prey populations. Taxon-specific differences in biomechanics or habitat use, among other factors, may lead to variable functional response forms or parameter values (attack rate, handling time). Based on a review of 189 individual functional response fits, we find that these predator guilds differ in their frequency distribution of functional response types, with crustaceans exhibiting nearly double the proportion of sigmoidal, density-dependent functional responses (Holling type III) as predatory fishes. The implications of this finding for prey population stability are significant because type III responses allow prey persistence while type II responses are de-stabilizing and can lead to extinction. Comparing per capita predation rates across diverse taxa can provide integrative insights into predatory effects and the ability of predation to drive community structure.


2017 ◽  
Vol 22 (2) ◽  
pp. 159 ◽  
Author(s):  
Yaghoub Fathipour ◽  
Maryam Karimi ◽  
Azadeh Farazmand ◽  
Ali Asghar Talebi

The lifetime functional response and predation rate of Amblyseius swirskii Athias-Henriot on eggs of the two-spotted spider mite, Tetranychus urticae Koch were determined under laboratory conditions using cucumber leaf discs. Densities of 2, 4, 8, 16, 32, 64 and 128 prey were offered to 3, 4, 5, 6, 7, 12, 17, 22 and 27-day-old A. swirskii individuals. Based on the logistic regression, the functional response of twelve-day-old A. swirskii was type III, while the other ages showed type II. The Rogers model was used to estimate searching efficiency (a) and handling time (Th). The longest handling time (1.387±0.315 h) was observed in the protonymphal stage, while the shortest handling time and highest maximum attack rate (T/Th) were estimated at the age of seven-days (0.396±0.057 h and 60.67 prey/day, respectively). In the functional response experiments, results of the highest prey density used (128 eggs) showed that the highest number of prey consumed by A. swirskii individuals aged twelve and seventeen-days old (35.6 and 43.1 eggs, respectively). It is concluded that A. swirskii could be an efficient biological control agent of T. urticae at the middle-age of its life and at higher prey densities. 


2019 ◽  
Vol 3 (1) ◽  
Author(s):  
Jan Muhammad Mari ◽  
Shahnawaz Mari ◽  
Santosh Kumar ◽  
Riffat Sultana

Field studies on the efficacy of bio-control agents (lacewing and Trichograma) in the management of okra pests were carried out at the trial area of Entomology Section, Agriculture Research Institute, Tando Jam. Seeds of okra (Subz pari) were sown on 7th February 2017 in a complete randomized block design with three replications. The biocontrol agents, lacewing and Trichogramma (1300 eggs/card) each were released. Lacewing was found very effective against aphid, jassid and whitefly in the field. Aphid was found at early stage of crop and touched the maximum level in midFebruary, therefore its population decreased quickly. Jassid increased linearly and was high after 6th week of observation and then decreased subsequently till picking of the crop. On the other hand, whitefly population increased linearly till 9th week of observation and then decreased and eventually disappeared from the crop on 19th week of observation. Trichogramma was observed as a main natural enemy of spotted bollworm of okra and reduced bollworm population. The population of bollworm increased slowly till harvesting of the crop. It is concluded from the present study that both the bio-control agents successfully lowered the populations of sucking and chewing insect pests and bollworms of okra. Lacewing was found effective against sucking insect pests while Trichogram efficiently controlled bollworms and are recommended for field applications. These bio-control agents can also be incorporated in IPM strategy


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