Beneficial insects can be broadly categorized into those that are parasitoids and those that are predators.  Parasitoids are typically smaller than their prey and usually require only one host to complete their development.  Adults lay eggs and the developing larvae feed either internally or externally, depending on the species.  A parasitoid generally kills its host, but not as suddenly as a predator.  A good example of a parasitoid is a braconid wasp. Predators are generally larger than their prey and each predator normally requires several hosts to complete its development.  They are free-living and found in great abundance in nature.  Lady beetles, lacewings, spiders, and mantids are good examples of predators. 

1.  Damsel bugs

Damsel bugs are slender, cigar-shaped insects, tan to brown in color and about one-half inch (25 mm) long.  The wings are light smokey-colored.  The front legs are thick and made for grasping and holding prey.  Damsel bug nymphs resemble the adults except they have no wings and appear very fragile.  Both adults and nymphs feed on small, soft-bodied insects, worms and eggs.

Bigeyed bug adults are black with clear, silvery appearing wings.  They have large conspicuous eyes on the sides of  their head.  Adults are less than one-fourth inch (6mm) in length.  Nymphs also have enlarged eyes, are silvery or gray in color with small, black specks on their body.  Both adults and nymphs feed on small, soft-bodied insects, worms, and eggs. 

3.  Minute Pirate Bugs

Minute pirate bug adults are about 1/16 inch (1.5 - 2 mm) long, mostly black in color with white markings on their wings. Adults have an “X” pattern on their backs.  Nymphs

Lady beetle adults are oval-shaped insects that vary in color but usually have black or orange-red spots on their wing covers.  Lady beetle larvae are elongate, spindle-shaped, with spiny backs.  They are black, blue and orange in color with thick stubby legs.  Both adults and larvae are very active and feed on small, soft-bodied insects and insect eggs.  They are very effective aphid predators.  Lady beetle eggs are yellow to orange in color and are laid in clusters of five to twenty eggs.  Lady beetles are the most important insect predators on pecan

Lacewing adults have many veins in their wings, giving them a net-like appearance.  The wings are held roof-like over the back.  Adults are green or brown in color and some have characteristic golden eyes.  Adults are not predaceous.  Larvae are about one-half inch (25 mm) long, spindle-shaped, and have long, sharply-pointed, mandibles protruding from the front of their head. Larvae are tan and white in color with a warty or spiny appearance.  Lacewing larvae eat small, soft-bodied insects, eggs and worms.  The eggs of lacewings are small, green to whitish in color and are laid on a slender, thread-like stalk.  Lacewings are very important predators on pecan in late season.

6.  Syrphid flies

Syrphid fly adults are flies which are generally banded or spotted with bright yellow markings on a black body.  They are often confused with wasp or bees and have a characteristic hovering flight. Adults are not predaceous. Syrphid fly larvae are elongate, legless, slug-like maggots which are tan to greenish in color and about three-eighths of an inch (10 mm) long. They are important predators of aphids and other small, soft-bodied insects.

7.  Assassin bug

Assassin bug adults are flattened, oval bugs with narrow heads and a slender neck. They are brown or black in color with some species having red-colored markings.  They range in length from one-half to one and one-half inches (12-36 mm).  Nymphs are similar in shape, form, color and habits but have no wings. Both adults and nymphs feed on small soft-bodied insects, worms and eggs.

Spiders (Figure 1) and mites are nor insects, but these arthropods are very important predators in the orchard.  Many types of spiders are found in pecans.  They vary greatly in size and color.  Spiders prey on almost any insect that comes within their range. One group of mites, Phytoseilus spp., are particularly helpful in controlling plant feeding mites in pecans.

Several species of small parasitic wasps and flies may be observed in pecan orchards. Parasitic wasps vary in size.  Colors differ but most are brightly colored.  Wasps are often seen flying in and out of the plant canopy searching for hosts

C. PATHOGENS

Another group of organisms that aid in suppressing insect pests are disease causing organisms or pathogens.  Pathogens occur naturally and can be a very significant factor in reducing insect populations.  Insect diseases may be caused by bacteria, fungi, nematodes, protoza, rickettsiae, or viruses.  All of these live abundantly on and in the bodies of insects.  However, in nature, insect disease epidemics depend upon rather precise conditions of temperature, humidity, and host density.  It is quite common to see insects in an orchard that have been killed by disease.  Fungal pathogens often reduce pecan aphid populations very rapidly.

Direct utilization of the array of biological controls is not currently possible.  However, a pest management approach allows us to gain maximum benefit from naturally occurring beneficial organisms.