%iTATE khLAiL\ I H ,
E-523 OF MEFNRTMEN January 1941
CONTROLLING GRUBS OF THE SOUTHERN GREEN JUNE BEETLE IN LAWNS
By W. R. Walton, Division of Cereal and Forage Insect InvestigatIions
The southern green June beetle (Cotinis nitida (L.)), or fig-eate r,
-as it is sometimes called, is one of the most common and conspicuous insects of the South, and is injurious from New Jersey and the southern portions of
Pennsylvania, Ohio, Indiana, and Illinois southward to the Gulf. West of the Mississippi River it is-found in Kansas, Missouri, and Texas. The adult, a velvety-green beetle, frequently attacks fruit, especially figs, grapes, and
peaches, but more often the grubs cause complaint as pests of lawns, golf greens, gardens, and general farm crops. Only under exceptional conditions do the grubs destroy living plant roots. In lawns and golf greens the mounds
of earth thrown up by the grubs are unsightly and when trampled they pack in a layer of earth solidly over the surrounding grass, thus killing it in the spots attacked. Cereal and forage crops, more especially fall-sown crops in
the Southern States, such as alfalfa and oats, as well as newly seeded lawns, are destroyed by being uprooted by the constant burrowing of the grubs. In all cases the tunnelling and burrowing cause the ground to become porous to
such an extent as to increase evaporation, and the plants are injured
seriously from lack of moistaire.
The work of the grubs becomes evident by the middle of August, and
prompt action should be taken at that time because the grubs are then more readily killed than later on. Injury to lawns and golf greens is more
apparent in the fall of the year than at other times, although reports of injury in the spring are often numerous. Infestation by the green June
beetle is greatly -favored by heavy fertilizing with an animal manure.
In the fall the large grubs dig deep vertical burrows in the soil in
which to overwinter or hibernate, and at this time they attract notice by the mounds of earth, 3 inches or more in diameter, thrown out at the mouths of their burrows. These burrows may be distinguished from those of earthNorms by their considerably larger diameter and the larger quantities of
earth around them.
The grub of the green June beetle is nearly 2 inches long when full
grown, is more robust than those of any of the May beetles, and bears numerous bristly hairs. It has the habit of emerging from its burrow on warm, damp nights and crawling over the soil surface on its back, aided by the bristly hairs borne on it. This habit serves to distinguish this grub from those of the May beetles and other similar insects.
These grubs feed mainly on organic matter contained in the soil, although evidence indicates that they may feed on living vegetation under exceptional conditions. Because of their ingestion of soil they can be easily controlled by applications of lead arsenate to the soil, as hereinafter described.
The large, robust, velvety-green adults or beetles appear in July and
August. Flying in the bright sunlight, they are conspicuous because of their noisy flight and vivid green color. The wing covers and thorax are bordered with yellow. The eggs are laid in the soil, and upon hatching about 3 weeks
later the young grubs approach the soil surface. Here they attract notice by their tunnelling and throwing up of small heaps of soil like anthills. The
grubs become nearly full grown by the time cold weather arrives and hibernate or remain less active in their burrows until the approach of spring.
Becoming full grown in the last part of May, they pupate, and emerge
as beetles early in July. The full seasonal life cycle is shown in figure 1, which illustrates all the stages. It may be seen from this that the life cycle extends over a full year.
METHODS OF CONTROL
As is the case with the grubs of the May beetles, the most reliable method of control for the grubs of the green June beetle is the application of powdered lead arsenate to the infested soil. As these grubs feed mostly on the soil substances, the poison is readily swallowed and is fatal to the grubs. Lead arsenate is only slightly soluble in water and is not injurious
to the grasses commonly used for lawns or golf greens. The lead arsenate may be applied to the turf at the rate of 1 pound to 100 square feet of area. To obtain a uniform distribution, the arsenate should be thoroughly mixed with
sand or dry soil at the rate of 1 pound of arsenate to 1 peck of sand or soil. This mixture can be broadcast by hand or applied with a fertilizer distributor. Although lead arsenate in the dry form does not adhere readily to grass, enough of the material often remains on the grass to be a hazard to children and domestic animals. It is therefore advisable to wash the turf with water after the treatment has been completed.
REMEMBER THAT LEAD ARSENATE IS POISONOUS TO MAN AND ANIMALS AND SHOULD BE HANDLED WITH GREAT CARE. AVOID INHALING THE DUST AND PROTECT THE HANDS.
A thoroughly reliable though more tedious method of killing the grubs
is the injection of carbon disulfide into their burrows. These can be easily located by the mounds of earth thrown up by the grubs during the night following a heavy sprinkling the preceding evening. Carbon disulfide can be obtained at drug stores. It is a heavy liquid which evaporates rapidly when
exposed to the air or introduced into the soil, and the heavy poisonous vapor readily penetrates the burrows and kills the grubs. About 1 teaspoonful should be injected into each burrow.
Carbon disulfide injures vegetation when applied directly to it; a funnel should therefore be used, it being inserted into the hole before the required amount of the liquid is poured in. An oiler having a long curved spout is convenient for dosing the burrows. The opening of each burrow should be plugged with soil immediately after treatment, to prevent the escape of the fumes. CARE SHOULD BE EXERCISED IN HANDLING CARBON DISULFIDE BECAUSE IT IS INFLAMMABLE, AND ITS FUMES WHEN MIXED WITH AIR ARE EXPLOSIVE. IN FACT, IT RESEMBLES GASOLINE IN THIS RESPECT, AND THERE SHOULD BE NO FIRE OF ANY KIND NEAR WHEN THE LIQUID IS HANDLED.
Since the application of manures to lawns as fertilizers is known to attract infestation by the green June beetle, the substitution of a suitable
commercial fertilizer for manure is indicated for areas liable to such infestation. For this purpose the following formula, comprising a complete fertilizer, is recommended:
Nitrate of soda .................. ...... .............. pounds 100
Sulphate of ammonia ................................ do. 50
Sulphate of potash .................................. do. 100
Acid phosphate .......................................... do. 250
Raw bone meal ............................................ do 1,000
Tobacco dust (ground tobacco stems) do. 500 Total ................................ F 000
For lawns, apply early in the spring at the rate of 500 to 1,000 pounds per acre. The substitution of a chemical fertilizer for manure should not be expected immediately to reduce infestation in areas that have previously been fertilized with manure.
e49W 1W W9 1719.I)* *&W __e"6t A791- C t
Figure 1. --DiagrammAtic picture showing the life history of the green June beetle.
UNIVERSITY OF FLORIDA 3 1262 09224 7674