Elementary Study of Insects

<h2><SPAN name="Chapter_XIV" id="Chapter_XIV"></SPAN><span class="smcap">Chapter XIV</span> <br/><br/> THE SQUASH BUG</h2> <p class="cap"><span class="dcap">This</span> common blackish or earth-colored bug is usually called the squash stink-bug. It has a very disagreeable odor which gives it this name. When disturbed it throws off from scent glands a small quantity of an oily substance which produces this odor. This is a protection to it for few birds or animals care to feed on it. Most species of sap or blood sucking true bugs have a similar protecting odor.</p> <div class="figcenter"> <ANTIMG src="images/042.jpg" width-obs="357" height-obs="450" alt="" title="" /> Pumpkin in field covered with adults and nymphs of squash stink-bug.</div> <p>The squash bug feeds largely on squash and pumpkins. It has a slender beak with needle-like mouth parts which are stuck into the plant for extracting the sap. It feeds only on plant sap. When it can not get squash or pumpkins it will feed on watermelons, muskmelons and related crops. It is<span class="pagenum"><SPAN name="Page_100" id="Page_100">[100]</SPAN></span> very destructive to these crops. It not only extracts sap thus weakening the plant but it also seems to poison the<span class="pagenum"><SPAN name="Page_101" id="Page_101">[101]</SPAN></span> plant while feeding. In this way its bite injures the plant something like the effects of the bed-bug's bite on our flesh. It feeds first on the leaves and vines often killing them in a few days. Later it may cluster and feed on the unripe squashes or pumpkins in such numbers as to completely cover them. Every country boy or girl has seen these stinking bugs on pumpkins in the corn field, at corn cutting time in the fall.</p> <div class="figright"> <ANTIMG src="images/043.png" width-obs="203" height-obs="200" alt="" title="" /> Cluster of golden-brown eggs of squash stink-bug showing two recently hatched nymphs.</div> <p>The squash bug lives thru the winter as the matured winged insect. It flies from its food plant to winter quarters late in the fall. For winter protection it may enter buildings, hide under shingles on roofs, crawl into piles of lumber, under bark of dead trees or stumps or hide under any similar protection. When its chosen food crops begin to come up in the spring it leaves its winter home and flies in search of food. After feeding for a time the female lays patches of oval, flattened, gold-colored eggs set on edge. When<span class="pagenum"><SPAN name="Page_102" id="Page_102">[102]</SPAN></span> first deposited the eggs have a pale color but in a short time the golden color appears. In some cases only three or four eggs may be found in one patch while again there may be twenty or thirty of them. They are so brightly colored that they can easily be seen and most boys and girls have seen them on the leaves of squashes or pumpkins.</p> <p>In a few days after they are laid they hatch and out of each crawls a small, long-legged blackish or greenish<span class="pagenum"><SPAN name="Page_103" id="Page_103">[103]</SPAN></span> young bug called the nymph. These little fellows usually stay in a crowd hiding on the under side of a leaf. After feeding for a time their leaf begins to turn yellow and soon dies. Then they move to a new leaf. As they feed they grow rapidly and after shedding their skins they change to the second nymph stage. This shedding of their skins or molting occurs five times before they mature. Of course each time before the old skin or suit of clothes is discarded a new one is developed beneath. The females may continue to deposit eggs for later clusters of young. They become most abundant on the crop late in the fall. Just before cold weather sets in the adults again seek winter shelter.</p> <p>This is a very difficult insect to control. Since it feeds on liquid sap only it is impossible to kill it by spraying the crop with a poison such as arsenate of lead. It can not chew and swallow such poison. The young can be killed fairly well with a spray or dust<span class="pagenum"><SPAN name="Page_104" id="Page_104">[104]</SPAN></span> containing nicotine but such treatments are not effective against the adults or nearly mature nymphs. A better method is to destroy all the bugs possible in the fall before they go to the winter protection and then watch for and destroy the adults and the eggs masses in the spring when they appear on the young crop. If the first adults and the eggs and newly hatched nymphs are destroyed the crop can be protected against the destructive work later.</p> <h3><span class="smcap"><SPAN name="Observations_and_Field_Studies2" id="Observations_and_Field_Studies2"></SPAN>Observations and Field Studies</span></h3> <div class="figright"> <ANTIMG src="images/044.png" width-obs="226" height-obs="200" alt="" title="" /> Squash stink-bug adult and nymph extracting sap from squash.</div> <p>Plant a few squash hills in the garden in the spring and also plant a few seeds in rich dirt in discarded tin cans or flower pots. As the spring advances and the squashes start to vine watch for squash bugs on them. Examine in piles of lumber, stove wood and under bark for some of the bugs before they come to the squash hills. If any are found put them on the squash plants in flower pots and cover them with a<span class="pagenum"><SPAN name="Page_105" id="Page_105">[105]</SPAN></span> pint mason fruit jar. Watch for eggs to appear on the plants and also examine for eggs on the squashes in the garden. When eggs appear examine them carefully, measure them and write a brief description of them. Try to mash them between your fingers. When they hatch carefully study the young nymph and describe it. Can you see the slender beak which incloses the mouth parts? How many joints are there to the antennae? As the nymph grows watch it shed its skin. How does it do it? Where does its skin first crack? Save the cast skin<span class="pagenum"><SPAN name="Page_106" id="Page_106">[106]</SPAN></span> and try to follow the nymph thru all the nymph stages to the adult. Collect a bottle of the nymphs of varying sizes from the garden. Examine them and describe the different stages. Can you see the wings forming on the backs of the older nymphs? How many small wing pads are there? Examine the adult closely and write a careful description of it. Can you find where the secretion that causes the odor is produced? How long will the odor stay on your hands? Can you wash it off? Spread the wings of the adult and make a careful drawing of one front and one hind wing showing accurately the wing veins. In the garden try to protect all the hills of squash from the bugs except one or two used for your studies. Write a brief description of your methods of control.</p> <hr style="width: 65%;" /><p><span class="pagenum"><SPAN name="Page_107" id="Page_107">[107]</SPAN></span></p> <div style="break-after:column;"></div><br />