Pest Identification

Weeds
Dandelion
Dandelion can be a major weed problem for turf and ornamental managers. In turf, it forms clumps that cause poor footing for athletic fields and golf courses. When dandelion infests turfgrass and ornamental plantings, it forms dense circular mats of leaves that crowd out desirable species and reduce the vigor of those plants that survive. Because of the extensive root system of established plants, hand-pulling or hoeing to remove dandelion is usually futile unless done repeatedly over a long period of time.  Once a few plants become established in turfgrass or ornamental areas, their seed can be spread by wind or equipment.
Black Medic
Black medic, a member of the clover family, is a low-growing annual but  sometimes behaves as a perennial. Stems are hairy and branch at the base; branches are prostrate and spreading. Seed leaves are oblong. The first true leaf is simple and rounded. Subsequent leaves are compound and have 3 egg-shaped leaflets with somewhat toothed margins. Flowers are small and yellow and are arranged in short, spherical heads.
Thistle
This aggressive weed is difficult to control; for example, breaking up the roots by plowing only serves to increase the number of plants.  Flowering occurs during July and August.

Chickweed
Chickweed is as common as the dandelion, but because it is less conspicuous, fewer people recognize this little plant. The little leaves are in opposite pairs on the stem, with white flowers.
Plantain
Broadleaf plantain is a shallow mostly fibrous rooted perennial.  Care should be taken to assure that roots are thoroughly removed. Close mowing prevents seedhead formation and helps to prevent spread. Good turf density is important as broadleaf plantain competes by shading other plant species with its broad rosette of leaves.

Insects

White Grubs
White grub are the C-shaped larvae of a large group of beetles called scarabs. (Japanese beetle, May and June beetles) White grubs can attack turfgrasses and destroy your lawn.
White grubs eat organic matter including the roots of plants. Therefore, damage first appears to be drought stress. Heavily infested turf first appears off color, gray-green, and wilts rapidly in the hot sun. Continued feeding will cause the turf to die in large irregular patches. The tunneling of the larvae cause the turf to feel spongy under foot and the turf can often be rolled back like a loose carpet. Grub populations may not cause observable turf injury but predatory mammals such as skunks, raccoons, opossums, and moles dig in the turf in search of a meal.
Chinch Bug
The chinch bug is a common lawn insect that sucks sap from grass with its piercing mouthpiece. Chinch bug damage gives the appearance of small round dead patches (brownish-yellow grass) and opens up areas for weeds to become established. When not controlled, large sections of lawn may die. This is particularly true of sunny, dry areas near slopes and the edge of lawns. Chinch bugs also cause damage when they feed and inject a toxic saliva into the grass causing it to wilt and die.

A well fertilized and nutrient-rich area can withstand a chinch bug attack. Thus, good lawn care is the best prevention against chinch bug damage.
Information provided by Environment Canada
Sod Webworm
There are several species of caterpillars called sod webworms that can be highly destructive pests.The damage caused by sod webworms may first appear in early spring. The damage shows up as small dead patches of grass among the normally growing grass.
Crane Fly (Inset: Leather Jacket)
The larval stage of the Crane Fly feeds on the roots of grass causing yellow patches; they will also attack potatoes, strawberries, cabbages and lettuce if they are planted in newly cultivated grassland.
BillBug
Light infestations in lawns often produce small dead spots that look like the turf disease, dollar spot. Sometimes the damage looks like irregular mottling or browning in the turf. Heavy infestations can result in complete destruction of the turf, usually by August. The major problem with billbug damage is that it looks like a variety of other problems. Most turf managers confuse billbug damage with drought, disease, chinch bugs, greenbugs or white grubs. Billbug damaged turf turns a whitish-straw color rather than the yellow caused by greenbugs. Soil under damaged turf is solid, not spongy as in white grub attacks.

Diseases

Crabgrass

How to Kill Crabgrass
Getting Rid of Crabgrass Tip By: David Beaulieu
Killing Crabgrass With Preemergent Herbicides
The lawn weed, crabgrass (Digitaria spp) is a warm-season annual weed, which means it reproduces by seed. People often ask me how to kill crabgrass. The short answer: applying preemergent herbicides at the right time is the best way to kill crabgrass.

Preemergent Herbicides for Killing Crabgrass: When to Apply
To get rid of crabgrass (see pictures at right), it helps to know its life cycle. When spring soil temps (at a depth of 2″-3″) reach 55-60 degrees Fahrenheit, the first crabgrass (also spelled “crab grass”) seed will germinate. From mid-summer to fall, crabgrass produces seed. The crabgrass plants (but not the seeds) are killed by frosts in autumn.

Preemergent herbicides (also spelled “pre-emergent”) come in either granular or liquid form and kill crabgrass seedlings as they germinate.

Think of preemergent herbicides as forming an invisible shield across the soil surface that stops emerging crabgrass dead in its tracks. This shield image will serve as a reminder not to practice core aeration on lawns after applying preemergent herbicides, since doing so would only “puncture” the shield. Aerate lawns beforehand, instead.

As their name suggests, preemergent herbicides kill crabgrass at a specific time: before its seedlings emerge. For success in getting rid of crabgrass in this manner, timing is of the essence. Apply preemergent herbicides before germination, but not too far ahead. Crabgrass germination coincides approximately with the blooming of the lilac bushes. Thus the old saying that preemergent herbicides should be applied sometime between the time the forsythia bushes (which precede the lilacs by a few weeks) stop blooming and the lilac bushes begin blooming.

Types of Preemergent Herbicides for Killing Crabgrass
There are many different types of preemergent herbicides for killing crabgrass. “Weed and feed” products often contain preemergent herbicides, although some question whether their concentration is strong enough to be effective. I will focus on 1 preemergent herbicide: Dimension

Dimension (active ingredient, dithiopyr) is safe to use on most lawn grasses (check label first) and provides long-lasting coverage — an important consideration, since not all crabgrass seed germinates at once. Thus Dimension will kill later-germinating crabgrass, too. Dimension also displays some effectiveness as a postemergent herbicide.

Using Preemergent Herbicides for Killing Crabgrass: DOs and DON’Ts

Do:

• Irrigate afterwards: water activates preemergent herbicides.
• Re-apply preemergent herbicides, if you question your product’s coverage. Because crabgrass seedlings do not all germinate at once, re-application can kill some of the later-germinating crabgrass.
• Follow label directions and apply the proper rate. Measure the lawn area and calibrate your spreader carefully.

• Dethatch or aerate the lawn after applying preemergent herbicides.
• Apply pre-emergent herbicides on new sod.

• Fertilize (compost is fine) more heavily in autumn than spring. By autumn, frosts will have already killed any crabgrass.
• Don’t let bare spots remain uncovered for long, else opportunistic crabgrass will take root. In the fall, fill in those bare spots by overseeding.
• When irrigating the lawn, water more deeply and less frequently. Crabgrass is a notoriously shallow weed.
• Mow “high”, leaving the lawn grass at a height of 2 1/2″-3″. This will allow the lawn grass to “protect its own turf” better, depriving crabgrass seeds of the light they need to germinate.