Population Dynamics in Biological Control

2017 ◽  
pp. 149-176
Author(s):  
George E. Heimpel ◽  
Nicholas J. Mills
Keyword(s):  
Biological Control ◽  
Population Dynamics

scholarly journals The influence of two wildfires and biological control agents on the population dynamics of Melaleuca quinquenervia in a seasonally inundated wetland

2021 ◽  
Vol 14 (1) ◽  
pp. 3-8
Author(s):  
Philip W. Tipping ◽  
Melissa R. Martin ◽  
Jeremiah R. Foley ◽  
Ryan M. Pierce ◽  
Lyn A. Gettys
Keyword(s):  
Biological Control ◽  
Population Dynamics ◽  
Seedling Recruitment ◽  
Additional Treatment ◽  
Seed Rain ◽  
The Other ◽  
Melaleuca Quinquenervia ◽  
Biological Control Agents ◽  
Seedling Mortality ◽  
Sapling Growth

AbstractThe potential of Melaleuca quinquenervia (Cav.) S.T. Blake to reinvade cleared areas was evaluated over a 13-yr period that included two wildfires and the introduction of biological control agents. The first wildfire occurred in 1998 and was followed by a mean of 591.5 recruited seedlings m−2. Recruits from that fire were cleared 7 yr later in July 2005 for a second experiment to evaluate seedling recruitment into cleared areas. Seed rain, seedling recruitment and mortality, and sapling growth rates were measured in four plots located around individual large reproductive trees. A second natural wildfire in 2007 burned through those plots, leading to increases in seed rain followed by a pulse in recruitment of 21.04 seedlings m−2, 96.5% fewer than after the 1998 fire. Recruits in half of the plots around each tree were then treated with regular applications of an insecticide to restrict herbivory by biological control agents, while herbivory was not restricted in the other half. There was no difference in seedling mortality between treatments 1,083 d post-fire (2007) with 96.6% seedling mortality in the unrestricted herbivory treatment and 89.4% mortality in the restricted herbivory treatment. Recruits subjected to the restricted herbivory treatment grew taller than those in the unrestricted herbivory treatment, 101.3 cm versus 37.4 cm. Many of the recruits were attacked by the biological control agents, which slowed their growth. Although solitary M. quinquenervia trees retain some capacity to reinvade areas under specific circumstances, there was a downward trend in their overall invasiveness at this site, with progressively smaller recruitment cohorts due to biological control agents. Land managers should prioritize removing large reproductive trees over treating recently recruited populations, which can be left for many years for the biological control agents to suppress before any additional treatment would be needed.

Biological control of the cassava mealybug, Phenacoccus manihoti by the exotic parasitoid Epidinocarsis lopezi in Africa

1988 ◽  
Vol 318 (1189) ◽  
pp. 319-333 ◽  
Keyword(s):  
Biological Control ◽  
Population Dynamics ◽  
South America ◽  
Reproductive Potential ◽  
Field Studies ◽  
Phenacoccus Manihoti ◽  
Epidinocarsis Lopezi ◽  
Southwestern Nigeria ◽  
Cassava Mealybug ◽  
Accidental Introduction

Since its accidental introduction into Africa, the cassava mealybug (CM) has spread to about 25 countries. The specific parasitoid Epidinocarsis lopezi , introduced from South America, its area of origin, into Nigeria in 1981, has since been released in more than 50 sites. By the end of 1986 it was established in 16 countries and more than 750 000 km 2 . In southwestern Nigeria, CM populations declined after two initial releases, and have since remained low. During the same period, populations of indigenous predators of CM , mainly coccinellids, have declined, as have indigenous hyperparasitoids on E. lopezi , because of scarcer hosts. Results from laboratory bionomic studies were incorporated into a simulation model. The model, field studies on population dynamics, and experiments excluding E. lopezi by physical or chemical means demonstrate its efficiency, despite its low reproductive potential.

scholarly journals Population Dynamics of Native Parasitoids Associated with the Asian Chestnut Gall Wasp (Dryocosmus kuriphilus) in Italy

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Tiziana Panzavolta ◽  
Francesco Croci ◽  
Matteo Bracalini ◽  
George Melika ◽  
Stefano Benedettelli ◽  
...  
Keyword(s):  
Biological Control ◽  
Population Dynamics ◽  
Pest Control ◽  
Climatic Conditions ◽  
Strong Fluctuation ◽  
Gall Wasp ◽  
Dryocosmus Kuriphilus ◽  
Native Parasitoids ◽  
Parasitism Rates ◽  
Indigenous Parasitoids

Native parasitoids may play an important role in biological control. They may either support or hinder the effectiveness of introduced nonnative parasitoids released for pest control purposes. Results of a three-year survey (2011–2013) of the Asian chestnut gall wasp (ACGW) Dryocosmus kuriphilus Yasumatsu (Hymenoptera: Cynipidae) populations and on parasitism rates by native indigenous parasitoids (a complex of chalcidoid hymenopterans) in Italian chestnut forests are given. Changes in D. kuriphilus gall size and phenology were observed through the three years of study. A total of 13 species of native parasitoids were recorded, accounting for fluctuating parasitism rates. This variability in parasitism rates over the three years was mainly due to the effect of Torymus flavipes (Walker) (Hymenoptera: Torymidae), which in 2011 accounted for 75% of all parasitoid specimens yet decreased drastically in the following years. This strong fluctuation may be related to climatic conditions. Besides, our data verified that parasitoids do not choose host galls based on their size, though when they do parasitize smaller ones, they exploit them better. Consequently, ACGWs have higher chances of surviving parasitism if they are inside larger galls.

Sign in / Sign up

Export Citation Format

Share Document