Bosvogels

Imidacloprid is a Recommended Insecticide for Control of Many Insect Infestations in US Forests

There are many kinds of insects that live in forests without occurring in damaging numbers. However, a few may develop occasionally into serious local infestations. Pesticide applications may be utilized for prevention of potential insect population buildup and suppression of outbreaks that threaten the vigor as well as survival of trees. Imidacloprid is recommended for the control of Balsam woolly adelgid, Hemlock woolly adelgid (eastern and Carolina hemlock), Aphids (various hardwoods and conifers), Emerald Ash Borer (Ash), Nantucket pine tip moth (2 and 3 needle pines only), and Sawflies (Virginia pine sawfly, introduced pine sawfly, red-headed pine sawfly).

Imidacloprid is used to control the hemlock woolly adelgid in the eastern hemlock forests of the United States

The hemlock woolly adelgid (HWA), a native of Asia, a 1/32 inch long reddish purple insect that lives within its own protective coating, is a threat to eastern hemlock forests, and eastern and Carolina hemlock of all sizes are susceptible. The HWA came from Asia without any of the natural enemies that keep populations in check in its native range. HWA was first reported in the eastern US in Virginia in the mid 1950's. Since then, it has spread north to Connecticut and south through North Carolina. It reached eastern Tennessee in 2002, and was first reported in eastern Kentucky in spring 2006. Systemic insecticides containing the active ingredient imidacloprid can be used as soil drenches or injections to control the HWA.

Imidacloprid, Found in Most Homeowner Insecticides, is Translocated to Nectar and Pollen and Kills Good Bugs

There are multiple ways that plants in urban landscapes can contain imidacloprid-contaminated nectar, since it is commonly applied in the landscape for many pests and many greenhouse plants are treated with prior to sale and transplanting. Imidacloprid may persist in nectar for a long time, since soil applications were effective against foliar pests for 1 to 2 years in containers and landscape trees. Injections of concentrated volumes of imidacloprid applied to trees trunks and roots were effective for 12 months for ash and linden. A soil application of imidacloprid to Eucalyptus tree resulted in 500 ppb in nectar and pollen, which will kill any insect feeding on nectar and pollen. Tree injections of imidacloprid at flowering are cause for concern, since linden flowers are a good source of nectar and pollen for bees, butterflies, and other beneficial insects.

Imidacloprid Protects Trees & Shrubs from Borer Damage in the United States

Nearly all shade trees and many shrubs are subject to borer attack, the tunneling of immature beetle or moth larvae through the cambium, sapwood or heartwood of the host plant. The emerald ash borer is now one of the most destructive non-native insects in the United States. The potential damage of this insect rivals that of Chestnut blight and Dutch Elm Disease. Since its accidental introduction into the United States and Canada in the 1990s, and its subsequent detection in 2002, it has spread to 14 states and adjacent parts of Canada. It has killed at least 50 to 100 million ash trees so far and threatens to kill most of the 7.5 billion ash trees throughout North America. Traditionally, borers have been treated with a trunk spray application of insecticide that kills the newly hatched insects before they tunnel into the plant. However, imidacloprid, a systemic insecticide that is applied as a soil drench around the base of target plants, is making borer control easier and targeting the small larva as they chew their way into the plant. It has a twelve-month residual effect. The chemical is absorbed by the plant's root system and moved throughout it's trunk, branches and foliage.

Soil injections of imidacloprid are frequently used to control insect pests on trees

Soil injections of imidacloprid are effective at preventing attack by the walnut twig beetle, a very aggressive beetle that will attack both healthy and stressed trees. Imidacloprid can also be injected directly into the trunk or soil so there is no public contact. Soil injections of imidacloprid are also very effective against Elm leaf beetles, a cyclic pest, European elm scale, one of the most widespread and destructive scale insects, Hawthorn mealybug and Kermes scale, which affects pin oak and red oak trees.

Long-term population dynamics and decline of the Tree Sparrow in Baden-Württemberg (Germany)

For almost 60 years the Baden-Württemberg forestry administration has been documenting the results of its nestbox monitoring scheme. The number of boxes rose from 40,000 around 1950 to 180,000 in the 1980s/1990s. For this study, 80,412 successful nests of the Tree Sparrow Passer montanus were evaluated out of the 3,4 million nestboxes monitored up to 1996. Since the Tree Sparrows in this survey mostly breed at woodland edges, but forage almost exclusively in agricultural land, the results reflect the general trend for the species in SW Germany. Until 1971 the species bred with constant occupancy rates that varied regionally between 0.5 and 5 % of all nestboxes. After that year the proportion increased, reaching rates of 15 % in the Rhine Valley and regionally of more than 30 %. After 1980 the nestbox population collapsed; the drop in the intensively cultivated Rhine Valley was from 15 % to 2 %. The increase in the 1970s is thought to have resulted from the prohibition of DDT. The permanent and continuing decline since 1980 indicates that developments in agriculture have been responsible for the later long-term negative population trend. Areas of intensive agriculture below an altitude of 200 m show the highest rates of decline.

De broedpopulatie van de kuifmees is sinds 1990 gedaald

De kuifmees Parus cristatus is een talrijke broedvogel die voornamelijk in naaldbossen broedt, soms ook in groepen naaldbomen, die tussen loofbomen en in parken staan. In tegenstelling tot de koolmees en pimpelmees is de kuifmees zelden in tuinen te zien, alleen als er naaldbomen in de omgeving aanwezig zijn. Zijn voedsel bestaat in de zomer uit insecten, insectenlarven, spinnen en andere kleine diertjes. In het najaar en de winter eet hij vooral zaden van naaldbomen. De kuifmees nestelt in zelfgemaakte holen in vermolmd of heel zacht hout. In Nederland broeden minstens 20.000 tot 30.000 paren kuifmezen. Volgens de gegevens van SOVON is er sinds 1990 een significante afname van het aantal broedvogels van <5% per jaar. Ook in Frankrijk, Zweden en Rusland nam de broedpopulatie in de jaren 1990 af (gegevens Birdlife International, zie bijlage).

De broedvogelpopulatie van de sijs vertoont sinds 1990 een significante afname

De sijs Carduelis spinus is in Nederland vooral een wintergast, maar tegenwoordig broedt hij ook in ons land. In de sparrenbossen van Scandinavië is de soort erg talrijk en het nest wordt meestal in een naaldboom gemaakt. De sijs eet zaden van naaldbomen, elzen, berken en andere bomen, knoppen en insecten. Grote aantallen sijzen bevolken in de winter Nederlandse tuinen. We kunnen de sijs dan regelmatig aantreffen op vetbollen en netjes met pinda’s die we in de tuin hebben opgehangen. In de periode vóór 1970 was de sijs een zeer schaarse broedvogel in Nederland. In het begin van de jaren '70 nam de stand toe naar 25-30 paren, later 300-700 paren en begin jaren '80 tot zo'n 1.800 -2.400 paren in 1992. Uit tellingen in 1998 bleken 500 - 1.200 paren in Nederland gebroed te hebben. Volgens de gegevens van SOVON vertoont de broedvogelpopulatie van de sijs sinds 1990 een significante afname van <5% per jaar. De Europese populatie sijzen was in de jaren 1990 grotendeels stabiel (gegevens Birdlife International, zie bijlage).

Sterke afname van de tjiftjaf in Frankrijk en Belgie in de jaren 1990

De tjiftjaf (Phylloscopus collybita) komt in heel Europa voor en is een zeer algemene broedvogel in Nederland. De Tjiftjaf lijkt als twee druppels water op de Fitis, maar door middel van de zang zijn de fitis en de tjiftjaf eenvoudig te onderscheiden. Tjiftjaffen zijn bosvogels die houden van een rijke ondergroei; veel struikgewas en lage bomen. De vogel eet voornamelijk insecten en fourageert vaak op de grond. Volgens SOVON was er in Nederland sinds 1990 geen verandering in het aantal broedvogels, maar in Frankrijk en Belgie ging de tjiftjaf in de jaren 1990 sterk achteruit. Ook in Zweden, Finland, Griekenland en Ierland daalde het aantal het aantal broedvogels in de jaren 1990 (gegevens Birdlife International, zie bijlage).

De fitis gaat sinds de jaren 1990 in grote delen van Noord-West-Europa achteruit

De fitis Phylloscopus trochilus komt tijdens het broedseizoen (maart tot augustus) in geheel Midden- en Noord-Europa voor, en broedt in hoge dichtheden in venen, jonge bossen en heiden. In open agrarisch gebied is de soort veel minder algemeen. Fitissen broeden op de grond - bij voorkeur tussen grassen - maar hebben beslist enkele bomen nodig als zang- en uitkijkpost. Hun voedsel, dat voornamelijk bestaat uit insecten zoals muggen, rupsen en andere ongewervelden, wordt vooral in struwelen gezocht. Volgens SOVON neemt de broedpopulatie sinds 1990 af. Ook in andere delen van Noord-West-Europa ging de fitis in de jaren 1990 achteruit (gegevens Birdlife International, zie bijlage).