How do you tell the difference between a squash bug (pest) & a damsel bug (beneficial)?

There are some insect species that look very similar to me.  I grow squash, along with other vegetables and would like to know if there is any quick way to spot the difference between these 2 insects?

**Squash Bug – Vegetables**

*Adults and nymphs suck leaf sap leaving numerous small white dots, known as stipples*

Appearance

* **Eggs**: Shiny, elliptical, rubbery, bronze colored; in clusters of about 20 eggs.
* **Nymphs**:  Newly hatched nymphs are pale green with black legs, and very gregarious. Five instars (growth stages) occur over about a month. Older nymphs are shades of gray in color and also have black legs.

  

*Squash bug nymph*  

**Adults**: Moderately large true bugs (have a triangular shaped thorax behind head) about 5/8" long, dark brownish gray in color. These gregarious bugs have piercing-sucking mouthparts and flattened bodies, with alternate light and dark markings around the edge of the abdomen.

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And your ‘Damsel Bug”

**Parasitoids - Tachinid Fly (Diptera)**

*Tachinid fly eggs laid on hornworm caterpillar* *(left), Tachnid fly eggs on Japanese beetle (right)*

People may be surprised to learn there are many beneficial flies that prey on garden pests. In fact, parasitoid flies are second only to parasitoid wasps in the sheer magnitude of pest insects they kill. There are 12 families of flies with thousands of species in which some members are parasitoids, but of these the tachinids are the most important. Most tachinids are endoparasites, which means that the developing larvae (maggots) feed within their hosts. Adult female tachinid flies employ a variety of methods to ensure their young will have ready access to food as they grow: some lay eggs on leaves to be eaten by caterpillars, others insert eggs or maggots directly into the host, and still others attach eggs or maggots to the outside of the host. Eggs consumed by the host or inserted by the mother hatch into maggots inside the victim. Eggs affixed to the skin of prey hatch and the maggots bore into the body of the host. Safely inside, the maggots complete their development, consuming their host as they grow.

**Pest(s)/Insects they fed on**

Tachinid flies most commonly parasitize the immature life stages (eggs, larvae or caterpillars, nymphs, and/or pupae) of beetles, butterflies, and moths, but also earwigs, grasshoppers, sawflies, and true bugs. Feather legged fly (*Trichopoda pennipes*) attacks stink bugs and leaf footed bugs, including squash bug and green stink bug. *Istocheta aldrichi* parasitizes adult Japanese beetles.  

 

**Appearance**

**Eggs:** Most tachinids lay small (up to 1/20” in size), oblong, white or grayish eggs.  

**Larvae (maggots):** usually develop within the host and are not seen.  

**Pupae:** Are commonly small, dark reddish, oblong cases.  

**Adults:** Many resemble house flies in size and color. They have robust bodies; are usually gray, black, or striped in color; with stout, hairy bristles protruding from the tip of the abdomen. The Feather legged fly is bright orange with velvety black head and thorax; with dark legs (hind legs have a fringe of short, black hairs); yellow feet; large, brown eyes; and brown and black wings.

-Birdy

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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