scholarly journals Comparing Chemical and Biological Control Strategies for Twospotted Spider Mites in Mixed Production of Ivy Geranium and Impatiens

2007 ◽  
Vol 17 (3) ◽  
pp. 322-327 ◽  
Author(s):  
Kiffnie M. Holt ◽  
George Opit ◽  
James R. Nechols ◽  
David C. Margolies ◽  
Kimberly A. Williams
Keyword(s):  
Biological Control ◽  
Chemical Control ◽  
Control Strategies ◽  
Phytoseiulus Persimilis ◽  
Predatory Mites ◽  
Plant Quality ◽  
Bedding Plants ◽  
Quality Ratings ◽  
Ivy Geranium ◽  
Twospotted Spider

Biological and chemical control strategies for the twospotted spider mite (TSM; Tetranychus urticae) were evaluated in a greenhouse experiment replicated over time in mixed production of ivy geranium (Pelgargonium peltatum ‘Amethyst 96’) and two impatiens cultivars (Impatiens wallerana ‘Impulse Orange’ and ‘Cajun Carmine’). Chemical control using the miticide bifenazate was compared with two release strategies for biological control using the predatory mite, Phytoseiulus persimilis. Specific treatments included 1) a single application of bifenazate at 0.3 g·L−1 formulation (22.6% a.i.); 2) a single release of predatory mites at a 1:4 predator to pest ratio based on sampled pest density; 3) a weekly release of predatory mites at numbers based on the area covered by the crop; and 4) an untreated control. TSM populations were monitored for 4 weeks. After another 4 weeks, when plants were ready for market, plant quality ratings were recorded. The number of TSM per leaf dropped for all treatments on all genotypes but increased in the untreated plants. On ivy geranium, the fact that there were significantly more TSM on untreated plants was not reflected in average plant quality, but it did reduce the proportion of containers rated as salable at full price compared with both chemical and biological control. On impatiens, both treatment and cultivar had significant effects on the mean plant quality rating and on the proportion of containers rated as salable at full price. The use of a sampling plan to determine the appropriate number of predators to release was as effective as the currently recommended management treatments for TSM in bedding plants.

Comparing Chemical and Biological Control Strategies for Twospotted Spider Mites (Acari: Tetranychidae) in Commercial Greenhouse Production of Bedding Plants

2009 ◽  
Vol 102 (1) ◽  
pp. 336-346 ◽  
Author(s):  
George P. Opit ◽  
Jamis Perret ◽  
Kiffnie Holt ◽  
James R. Nechols ◽  
David C. Margolies ◽  
...  
Keyword(s):  
Biological Control ◽  
Control Strategies ◽  
Spider Mites ◽  
Greenhouse Production ◽  
Bedding Plants ◽  
Twospotted Spider

scholarly journals Plant Age, Fertilization, and Biological Control Affect Damage Caused by Twospotted Spider Mites on Ivy Geranium: Development of an Action Threshold

2005 ◽  
Vol 130 (2) ◽  
pp. 159-166 ◽  
Author(s):  
George P. Opit ◽  
Yan Chen ◽  
Kimberly A. Williams ◽  
James R. Nechols ◽  
David C. Margolies
Keyword(s):  
Phytoseiulus Persimilis ◽  
Plant Size ◽  
Plant Quality ◽  
Plant Production ◽  
Economic Damage ◽  
Production Cycle ◽  
Action Threshold ◽  
Ivy Geranium ◽  
Leaf Distortion ◽  
Twospotted Spider

In three experiments, damage caused by twospotted spider mite (TSSM; Tetranychus urticae Koch) was correlated with the quality of ivy geranium [Pelargonium peltatum (L.) L'Her ex Aiton], and the action threshold for TSSM on ivy geranium was developed. Ivy geranium quality was measured as overall plant quality—plant size and form, and leaf greenness and glossiness—leaf browning, and leaf distortion. Young plants with high initial TSSM numbers (30 TSSM/plant) exhibited the greatest damage, suggesting that monitoring for TSSM early in the plant production cycle is necessary to prevent extensive damage. The leaf distortion index and overall plant quality were correlated with cumulative TSSM density and marketability in 4-week-old plants infested with 30 TSSM, whereas leaf browning was not correlated with either. Thus, either leaf distortion or overall plant quality can be used to measure economic damage resulting from TSSM. The action threshold for TSSM on ivy geranium was determined using overall plant quality. When the predatory mite, Phytoseiulus persimilis Athias-Henriot, is used to control TSSM, the action threshold was found to be 2 TSSM/leaf. Results also showed that fertilizer combinations of 8 or 24 mm nitrogen and 0.32, 0.64, or 1.28 mm phosphorus had no effect on cumulative TSSM density. When P. persimilis was released at predator: prey ratios of 1:60, 1:20, and 1:4, TSSM damage, measured as both leaf distortion and overall plant quality, was significantly reduced at 1:4 and 1:20, but not at 1:60. A 1:4 rate resulted in the most marketable plants. These results suggest that P. persimilis should be released at a rate of 1:4 when the TSSM action threshold is reached.

scholarly journals Overhead and Drip-tube Irrigation Affect Twospotted Spider Mites and their Biological Control by a Predatory Mite on Impatiens

HortScience ◽  
2006 ◽  
Vol 41 (3) ◽  
pp. 691-694 ◽  
Author(s):  
George P. Opit ◽  
Greg K. Fitch ◽  
David C. Margolies ◽  
James R. Nechols ◽  
Kimberly A. Williams
Keyword(s):  
Biological Control ◽  
Drip Irrigation ◽  
Phytoseiulus Persimilis ◽  
Predatory Mites ◽  
Predatory Mite ◽  
Management Program ◽  
Irrigation Method ◽  
Overhead Irrigation ◽  
Number Of Leaves ◽  
Twospotted Spider

The effects of overhead and drip tube irrigation on twospotted spider mite (TSMs) (Tetranychus urticae Koch) and predatory mite (PMs) (Phytoseiulus persimilis Athias-Henriot) populations, as well as the biological control of TSMs by PMs, were investigated on Impatiens wallerana Hook. f. `Impulse Orange'. To determine the effects of the two irrigation methods on TSM populations, plants were inoculated with female TSMs 6 weeks after seeding. Plants were then irrigated twice every three days, and TSM counts were taken 3 weeks later. To assess the effects of irrigation method on PMs, plants were inoculated with TSMs 6 weeks after seeding, PMs were released 10 days later, plants were irrigated about once per day, and the number of predatory mites on plants was counted 3 weeks after release. To assess the effects of irrigation method on the biological control of TSMs by PMs, plants were inoculated with TSMs and PMs were released as before, but then plants were irrigated either three times every 2 days or three times every 4 days using either drip or overhead irrigation. The number of TSMs on plants and the number of leaves showing TSM feeding injury were measured 3 weeks after predator release. Overhead watering significantly reduced TSM and PM populations as much as 68- and 1538-fold, respectively, compared to drip irrigation with microtubes. Perhaps more important, overhead watering with or without predators significantly reduced the number of leaves sustaining TSM feeding injury as much as 4-fold compared to drip irrigation. These results confirm the common observation that TSM infestations and injury may be reduced by irrigation systems that wet plant foliage. However, predators still reduced TSMs even though overhead irrigation had a suppressive effect on predatory mites. Predators are particularly useful for reducing TSM injury when plants are watered infrequently. Overhead watering could be used in tandem with biological control as a component of an integrated crop management program for TSMs in ornamental greenhouses by rapidly lowering TSM population levels in hot spots before PMs are released.

scholarly journals Control of Pest Grasshoppers in North America

Insects ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 566
Author(s):  
Wahid H. Dakhel ◽  
Stefan T. Jaronski ◽  
Scott Schell
Keyword(s):  
Biological Control ◽  
North America ◽  
Human Health ◽  
Chemical Control ◽  
Control Strategies ◽  
Special Focus ◽  
Main Method

Grasshoppers (Orthoptera: Acrididae) frequently inflict damage on millions of hectares of western rangelands and crops. The main method of controlling grasshopper outbreaks consists of covering their infestations with chemical insecticides. Although it is relatively cheap, fast, and efficient, chemical control bears serious risks to human health, non-target organisms, and the environment. To overcome this challenge, biological control is a less environmentally hazardous alternative to traditional, synthetic insecticides. This paper reviews strategies that could be used as effective ways to control such pests with a special focus on effective bait formulations that might provide a key model in developing biological control strategies for the grasshopper population.

A Dynamical Analysis of a Piecewise Smooth Pest Control SI Model

2015 ◽  
Vol 25 (05) ◽  
pp. 1550068 ◽  
Author(s):  
Bing Liu ◽  
Wanbo Liu ◽  
Fennmei Tao ◽  
Baolin Kang ◽  
Jiguang Cong
Keyword(s):  
Biological Control ◽  
Control System ◽  
Pest Control ◽  
Chemical Control ◽  
Sliding Mode ◽  
Control Strategies ◽  
Piecewise Smooth ◽  
Dynamical Analysis ◽  
Pest Population ◽  
Si Model

In this paper, we propose a piecewise smooth SI pest control system to model the process of spraying pesticides and releasing infectious pests. We assume that the pest population consists of susceptible pests and infectious pests, and that the disease spreads horizontally between pests. We take the susceptible pest as the control index on whether to implement chemical control and biological control strategies. Based on the theory of Filippov system, the sliding-mode domain and conditions for the existence of real equilibria, virtual equilibria, pseudo-equilibrium and boundary equilibria are given. Further, we show the global stability of real equilibria (or boundary equilibria) and pseudo-equilibrium. Our results can provide theoretical guidance for the problem of pest control.

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